Assembly constraints determine how components in the assembly fit together. As you apply constraints, you remove degrees of freedom, restricting the ways components can move. You can assign maximum, minimum, and resting position values to specify the allowable range of motion for a constraint.
What types of assembly constraints are available?
The Place Constraints dialog box creates constraints to control position and animation. Motion constraints do not affect position constraints.
The Assembly tab has the following constraints to control position:
The Assembly tab also supports user-defined constraint limits. You can define a minimum, maximum, and resting position for constraints in the assembly tab.
The Motion tab has the following constraints to specify intended motion ratios between assembly components:
- A rotation-rotation constraint specifies rotation of one part relative to another part using a calculated or specified ratio.
- A rotation-translation constraint specifies rotation of one part relative to translation of a second part.
How are constraints created?
Constraints are created using either the Constrain command or the Assemble command.
Constrain command
You select a constraint type to update the Place Constraint dialog box then select the objects to constrain. In addition to creating the constraint, you can change the browser name and apply limits.
To help you position components correctly, you can preview the effects of a constraint before it is applied. After you select the constraint type, the two components, and set the angle or offset, the components move into the constrained position. You can adjust settings as needed, and then apply them.
Assemble command
You select the objects to constrain, and then select the type of constraint to apply. A mini toolbar displays in the graphics window instead of a dialog box. Assemble automatically selects valid constraint types based on your geometry selections. For example, if you select planar faces only the Mate-Mate, Mate-Flush, and Angle-Directed constraint types are displayed in the list. If your first selection is a circular edge, only the Insert-Opposed and Insert-Aligned constraints are listed, and your second selection is limited to a circular edge.
The Assemble command always moves the first selected component to the second selection. If necessary, existing constraints or grounded status are relaxed to allow the first component to move. When you exit the Assemble command, all new and existing constraints are calculated. If there is a conflict, the Assemble Constraint Management dialog displays so you can suppress or delete the constraints. Use this workflow to change the location of a component when you are unsure how it was constrained. You can reposition the component and then resolve any constraint conflicts.
Some constraint types (Motion, Translation, Angle-Undirected, and Angle-Explicit Reference Vector) are not supported in the Assemble command. Also, you cannot change the constraint name or apply limits. You can edit the constraint after it is created to change those settings.
Grip Snap command
Grip Snap moves a component relative to another component or reference geometry. It does not create constraints, but you can ground the component when you have positioned it. You can change several Grip Snap settings in the Application Options. For example, you can select whether it ignores the grounded status while moving components.
What are constraint limits?
Constraint limits use specified values to define the allowable range of motion for components that move or rotate. You can specify a Maximum, a Minimum, and a Resting Position for a constraint in the Assembly tab. The Resting Position uses the value specified in the Offset box. A constraint with limits is identified in the browser by a +/- symbol.
Contact sets require physical contact with other components to determine the limits. Constraint limits use assigned values to limit movement and do not require physical contact. Use constraint limits to evaluate a design based on known maximum, minimum, and resting values.
TipAs with contact sets, consider assembly performance when you use constraint limits. For best performance, use constraint limits to evaluate your design and then edit the constraint and clear the check boxes. The limit values are stored with the constraint and remain available when you reactivate the limits.
Should I use constraint limits, contact sets, or dynamic simulation for moving parts?
If you are designing a mechanism with moving parts, simulating the motion is a key component of the digital prototyping process. Before deciding on the appropriate method, consider the following:
- Use constraint limits to define the range of allowable movement or rotation. You can specify a maximum, minimum, and resting position value for constraints in the Assembly tab.
- Motion constraints use defined rotational or rotational-translational ratios to depict movement between components. Use motion constraints for a lightweight method to verify movement such as the proper gear ratio.
- Contact Sets use physical contact between components to limit movement. If interference is detected, the components do not move. This method requires more computation than a motion constraint.
- Dynamic simulation uses physical properties like mass, friction, inertia matrix, and load definition to provide information on how the components act in the physical world. Use the Inventor Simulation Suite to study the influence and result of actual forces on your design. This method requires the most computation but provides the most accurate results. A link to Inventor Studio enables realistic animation recording of the motion.
- Inventor Studio enables animation of assembly constraints and positional representations to create mechanistic motion. Image and video output of realistic or illustrative content is the main use for Inventor Studio.
What is a Layout constraint?
Layout constraints are created when you execute Make Components. Layout constraints define the relationship between the layout and parts push derived from the layout. The Layout constraint comprises flush constraints between the three primary planes of the layout and derived parts, and a zero degree angle constraint between the Z axes of the layout and derived parts.
Layout constraints provide certain behaviors that are useful in skeletal modeling:
- Constrain to Layout Plane - constrains the component to the layout plane, at a fixed offset, and allows component movement parallel to the layout plane. If not selected, your component can move perpendicular to the layout plane (along the Z axis of the layout part).
- Layout Controls Position - your layout part controls the X and Y position of the assembly component.
- Assembly Controls Position - you can move the component relative to its constraints and degrees of freedom. You can constrain this motion to 2D or 3D.
The default behaviors for layout constraints are initialized based on your sketch constraint relationships and options you select during Make Components. To changes behaviors for a component, right-click the component instance in the browser, select Layout Constraint in the context menu, and choose the appropriate position options.
You can modify layout constraints to achieve the target behavior. However, you cannot place new layout constraints except by the Make Components workflow.
How do constraints position components?
- The first part you place in an assembly is grounded. Its position is fixed, with the part origin coincident with the assembly origin.
- When you place the next part and constrain it to the grounded part, it moves to the grounded part. It fits together according to the type of constraint applied.
- As you add parts, add new constraints to position the new parts relative to the other assembled parts.
- After constraints are positioned, add motion constraints to control rotation and translation in the remaining degrees of freedom. You specify a ratio to set movement between two components.
How do drive constraints and motion constraints differ?
Drive constraints do not control motion between components, but simulate mechanical motion by driving a constraint through a sequence of steps for a single component. You can, however, animate two components by using Equation to create algebraic relationships between components. A drive constraint operation is a temporary animation.
Motion constraints specify motion ratios between components, either by rotation or by rotation and translation. Such constraints are useful for specifying motion of gears and pulleys, a rack and pinion. They can also specify motion between third-party components, such as a gearbox, and input and output shafts. Use work geometry and assembly constraints to limit the range of motion.
Can constraint names be modified?
After you place constraints, they are shown in the assembly browser. You can rename constraints to indicate which can be driven, for example. Constraints can be renamed in the browser or the Place Constraint dialog box.
Can constraints be retained on replaced components?
There are two ways to retain constraints for replaced components:
- Create the existing and replacement component from a common base (by using Save Copy As option).
- Use iMates.
iMates are constraint pairs in parts that define how a part fits together with other components each time it is placed in an assembly.
Convert existing assembly constraints to iMate definitions by right-clicking the component in the browser, and then selecting Infer iMates. You can also create iMates as you edit or modify a component.
What is a good strategy for creating constraints in complex assemblies?
To simplify constraining the members of a complex assembly, create several small assemblies; apply constraints as needed, then save each one as a separate file. This approach allows the subassembly to be constrained in upstream assemblies as a single unit.
Grouping parts in subassemblies also simplifies the process of using the parts in more than one assembly.
Procedures
Place Mate or Flush constraints in assemblies
A Mate constraint positions selected components face to face or with the faces flush. The geometry you select is usually a component face, but you can also select curves, planes, edges, or points.
You can place a Mate constraint three ways:
- On the ribbon, use to place a Mate constraint between two assembly components.
- On the ribbon, use to place a Mate constraint between two assembly components.
- Hold down ALT while you drag a component into position, automatically placing a Mate constraint.
To begin, place the components to constrain in an assembly file.
To use Constrain to place Mate or Flush constraints
Clear the check box to remove limits. Values are retained in an inactive state.
Show Me how to create a mate constraint |
To use Assemble to place Mate or Flush constraints
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To drag a component into position and place a Mate constraint
You can drag a component into position and automatically place a Mate constraint with no offset.
When you drag a cylindrical part over another cylindrical part or hole, the inferred Mate constraint is along the axes. If you position the dragged part over a component face, the system infers a mate between planar faces.
Kinematics mode for translated constraints
If the selected constraint was created with Make Components, you sometimes have the option to select between 2D and 3D Kinematics. See Set kinematics mode in the Make components procedure for more information.
NoteIf other components obscure selection, do one of the following:- Temporarily turn off visibility before you place a constraint. Click in the browser to select a component, and then right-click and select Visibility.
- To restrict selectable geometry to a specific part, select Pick Part First in the dialog box, and then click the component you want to constrain. Clear Pick Part First to restore normal selection mode.
Place Angle constraints in assemblies
Use the Constrain command or Assemble command to place an Angle constraint between two assembly components. An Angle constraint controls the angle between edges or planar faces.
To begin, place the components to constrain in an assembly file.
Use Constrain to place Angle constraints
NoteFor best results, make the third selection on a stationary component.
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Clear the check box to remove limits. Values are retained in an inactive state. NoteThe following rules apply to limits:
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Use Assemble to place Directed Angle constraints
- Click Apply and continue to define constraints.
- Click OK to create the constraints and exit the Assemble command.
- Click Undo to delete the selections and continue to define constraints.
- Temporarily turn off visibility before you place a constraint. Click to select a component, right-click, and then select Visibility.
- To restrict selectable geometry to a specific part, select Pick Part First in the dialog box, and then click the component you want to constrain. Clear the check box to restore selection mode.
Place Tangent constraints in assemblies
Use the Constrain command or Assemble command to place a Tangent constraint between assembly components. A Tangent constraint positions faces, planes, cylinders, spheres, cones, and ruled splines tangent to one another.
To begin, place the components to constrain in an assembly file.
Use Constrain to place Tangent constraints
Clear the check box to remove limits. Values are retained in an inactive state. Show Me how to create a tangent constraint |
Use Assemble to place Tangent constraints
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- Temporarily turn off visibility before you place a constraint. Click to select a component, right-click, and then select Visibility.
- To restrict selectable geometry to a specific part, select Pick Part First in the dialog box, and then click the component you want to constrain. Clear the check box to restore the selection mode.
Place Insert constraints in assemblies
Use the Constrain command or Assemble command to place an Insert constraint. An Insert constraint places a planar and axial mate as a single constraint between selected cylindrical faces or edges. For example, use an Insert constraint to position a bolt in a hole. The bolt is free to rotate, but is constrained plane to plane and axis to axis.
To begin, place the components to constrain in an assembly file.
Use Constrain to place Insert constraints
Clear the check box to remove limits. Values are retained in an inactive state.
Show Me how to insert a constraint |
To use Assemble to place Insert constraints
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- Temporarily turn off visibility before you place a constraint. Click in the browser to select a component, right-click, and then select Visibility.
- To restrict selectable geometry to a specific part, select Pick Part First in the dialog box, and then click the component you want to constrain. Clear Pick Part First to restore normal selection mode.
Create assembly constraints using the Assemble command
Assembly constraints maintain positions of components relative to one another in an assembly. Use the Assemble command to create constraints by selecting geometry first and then the constraint type. The geometry you select determines the available constraint type.
You can constrain only one component at a time with Assemble. When you finish defining constraints for a component, select OK to create the constraints and exit the command. Repeat Assemble to constrain the next component.
New constraints are not compared to existing constraints until you finish the Assemble command. If any constraint conflicts are found, the Assemble Constraint Management dialog box displays. Use this dialog box to diagnose and resolve the conflicts.
General workflow
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Specific workflows by constraint type
Place assembly constraints using ALT-drag
Assembly constraints maintain positions of components relative to one another in an assembly. Optionally, use the ALT-drag shortcut instead of using the Place Constraint dialog box or Assemble command.
- Click a planar face, linear edge, or axis to place a mate or flush constraint.
- Click a cylindrical face to place a tangent constraint.
- Click a circular edge to place an insert constraint.
- Select a mate or flush constraint.
- Select a tangent constraint inside or outside the selected cylindrical face.
- Select the direction of an insert constraint.
If the face you must constrain to is hidden, pause long enough to display the Select Other command. Cycle through the available selectable options, then click the center dot to confirm the selection and place the constraint.
A constraint symbol is displayed with both components in the browser.
Tips, Shortcut Keys
Use the ALT-drag shortcut to infer constraints. Press ALT, and then drag a component into the appropriate position. The inferred constraints are previewed in the graphics window as you drag over the affected components.
When constraining components using the ALT-drag shortcut, you can change the constraint type after you start dragging the first part.
Release ALT, and enter a shortcut key:
M or 1 | Changes to a mate constraint. Press the space bar to flip to a flush constraint. |
A or 2 | Changes to an angle constraint. Press the space bar to flip angle direction on the selected component. |
T or 3 | Changes to a tangent constraint. Press the space bar to flip between an inside and outside tangent constraint. |
I or 4 | Changes to an insert constraint. Press the space bar to flip insert direction. |
R or 5 | Changes to a rotation motion constraint. Press the space bar to flip rotation direction. |
S or 6 | Changes to a translation (slide) constraint. Press the space bar to flip slide direction. |
X or 8 | Changes to a transitional constraint. |
NoteIf you create constraint and forget which components are constrained to each other, click a constraint to highlight the constrained components.
Apply assembly constraints to sketch geometry
You can create assembly constraints between sketch geometry and geometry on other components. Lines, circles, points, and their vectors can be incorporated into constraint schemes. Sketch behavior is like any other component used in an assembly: it can be adaptive, is previewed before a constraint is placed, and can be edited in the assembly. |
To begin, do one of the following in an assembly file:
- On the ribbon, use to insert one or more components and a part file containing sketch geometry.
- On the ribbon, use to create the components and part file with sketch geometry within the assembly.
To constrain a component to sketch geometry: |
Find constraints in an assembly
Changes to assemblies during the design process can affect existing constraints causing them to conflict with others or become unsolvable. Designers must then locate the constraints in question to resolve the errors or to collect additional information.
You can locate all constraints in the assembly or locate the other half of a single assembly constraint.
Locate all constraints in an assembly
Locate the other half of a single constraint
There are two halves to every assembly constraint. When multiple constraints of one type exist, such as several Mate or Flush constraints, it can be difficult to locate the other half. To make constraints easier to locate, the browser automatically expands to show the other half of the selected constraint and highlights it.
Use Find to locate constraints
- Using the And/Or operators, select And to accumulate criteria or select Or to satisfy the search if either criteria is met.
- Specify Property. The Find command recognizes the active environment and offers search criteria based on the environment.
- Select a Condition.
- Specify a Value to complete the Property, Condition, Value statement.
Delete assembly constraints
If your constraint strategy or design requirements change, you can delete an assembly constraint.
In the browser, do the following:
TipAn alternate method for deleting a constraint is to select the constraint in the browser, and then press the Delete key.
In a complicated assembly, components can obscure the features or components whose constraints you want to delete. If you prefer, click the component in the graphics window to highlight it in the browser. Or in the browser, select the component, right-click, and then select Find in Window.
NoteIf you chose to display the contents of the browser using the Modeling View, constraints are listed under Constraints at the top of the browser. If you have difficulty determining which constraint applies to a component, display the browser contents using the Position View before you delete constraints.
Edit assembly constraints
You can edit the constraint type, offset, angle, selected components, and direction. If possible, constraints are retained through editing operations. Some constraints do not survive and must be reapplied.
NoteThis procedure presumes that the Position View is active. If you activated the Modeling View, all constraints for each assembly are collected below the assembly origin folder (although each part displays its features when expanded).
To edit only the offset or angle, highlight the constraint in the browser. Then click to open the edit box at the bottom of the browser. Enter the new value for the constraint, and then press Enter.
NotePredict Offset or Angle is only available when creating constraints.
Tips for editing constraints
- To make it easier to see which constraints are affected, the two participants of the constraint relationship highlight with different colors.
- If you must override a constraint value in a positional representation (not the master), you can right-click a constraint in the browser and select Modify (Override). In a master positional representation, right-click and select Modify.
- To locate the participants in a constraint, right-click a constraint in the assembly browser and select Isolate Components. Visibility is turned off for all components except the two components constrained together. To restore visibility, right-click an isolated component and select Undo Isolate.
Drive Constraints in assemblies
Use Drive Constraint on the context menu to simulate mechanical motion by driving a constraint through a sequence of steps. The Drive Constraint command is limited to one constraint, but you can drive additional constraints by using Equations to create algebraic relationships between constraints.
To begin, constrain two components together.
- Select the Drive Adaptivity check box to adapt components while maintaining the constraint relationship, if needed.
- Select the Collision Detection check box to check for interference.
- Set the Increment between steps by specifying either the value or the total number of steps. Enter a value or click the arrow to select Measure or a recently used value.
- Set the Repetition or Cycles of the sequence: Start/End runs once and returns to the beginning; Start/End/Start runs once forward, then once backward depending on the number of cycles set. Each motion is considered one cycle. For example, for a component to move out, set one cycle. To move out, in, and out again requires three cycles. Optionally, enter a value to run the sequence more than once.
After the sequence begins, click Stop, click Forward or Reverse, Step Forward or Step Reverse, or Go to Beginning or Go to End.
Show Me how to drive a constraint
TipTo record the driven constraint sequence, click More and set the AVI rate. Then click Record. Enter the file name with extension and click Save in the Save As dialog box. For an .asf or .wmv file, set the export options in the ASF Export Properties dialog box. After you close the ASF Export Properties dialog box, click Play in the Drive Constraint dialog box to create the recording.
Place Motion constraints between assembly components
Use the Constrain command to specify intended motion ratios between assembly components.
A Motion constraint maintains rotational or rotational-translational movement between components. You can specify the ratio or determine the ratio by picking geometry.
To specify the ratio for rotational components, select a circular face or edge on each component. To calculate the ratio based on relative size, select a cylindrical face on each component.
To specify the distance for rotational-translational components, select a circular face or edge on the rotational component and a linear edge on the translational component. You can calculate the distance based on circumference and length. Select a cylindrical face on the rotational component and a linear edge or sketched line on the translational component.
To begin, place the components to constrain in an assembly file.
Place Transitional surface constraints
Use the Constrain command to place a Transitional constraint between assembly components. |
A Transitional constraint maintains tangency between a (typically) cylindrical face and a contiguous set of faces on another part, such as a cam in a slot. You can slide the component along open degrees of freedom.
Place Constraint Set (constrain UCS to UCS)
References
Assembly constraints
Assembly constraints remove degrees of freedom between two selected components, positioning them relative to one another.
Constrain
The Place Constraint dialog displays and you select a constraint type. The dialog updates and you make the selections for that type of constraint.
Assemble
A mini toolbar displays in the graphics window instead of a dialog. As you select geometry, the list of constraint types updates based on those selections.
The first component always moves to the second component, even if the first component is fully constrained. If this causes constraint errors, the Assembly Constraint Management dialog lists the conflicting constraints so you can suppress or delete them.
You can only add constraints to one component at a time with Assemble. When you finish defining constraints for a component, select OK to create the constraints and exit the command. When you restart Assemble you select the next component you want to constrain.
The Constraint Type list updates as you select geometry to list only valid constraints. You can select a constraint type at any time to limit the type of geometry you can select. For example, if you select Insert- Opposed, you can only select circular edges. | |
Enter the offset or angle value. | |
The OK button creates the constraint and exits Assemble. | |
The Apply button creates the constraint and leaves Assemble active. | |
The Undo button clears any selections. | |
ESC | Press ESC to create any applied constraints and exit the Assemble command. |
Assembly constraints - Assembly tab
Assembly constraints remove degrees of freedom between selected components. Adaptive components can resize or change shape when constraints are applied.
Access: | , and then click the Assembly tab. |
Type and Solutions
Specifies the type of constraint and illustrates the solution used to position components before you apply the constraint. Change constraint type and place constraints when the dialog box is open. When you select a face, curve, or point (including midpoint), an arrow shows the default direction of the solution. Click constraint icons on the dialog box to change solution. Use constraint limits to define the range of allowable movement or rotation. You can specify a maximum, minimum, and resting position value for constraints in the Assembly tab.
A Mate constraint positions components face to face or next to one another with faces flush. Removes one degree of linear translation and two degrees of angular rotation between planar surfaces. | ||
A Mate constraint positions selected faces normal to one another, with faces coincident. Supports user specified limits and resting position. | ||
A Flush constraint aligns components next to one another with faces flush. Positions selected faces, curves, or points so that they are aligned with surface normals pointing in the same direction. Supports user specified limits and resting position. | ||
An Angle constraint positions edges or planar faces on two components at a specified angle to define a pivot point. Removes one degree of freedom in rotation or two degrees of angular rotation between planar surfaces. | ||
Directed Angle solution always applies the right-hand rule. Does not support user specified limits and resting position. | ||
Undirected Angle allows either orientation, thus resolving situations where component orientation flips during a constraint drive or drag. Supports user specified limits and resting position. | ||
Explicit Reference Vector Explicitly defines direction of Z axis vector (Cross Product) by adding a third pick to the selection process. Reduces tendency of angle constraint to switch to an alternate solution during a constraint drive or drag. This solution is the default. Supports user specified limits and resting position. | ||
A Tangent constraint causes faces, planes, cylinders, spheres, and cones to contact at the point of tangency. Tangency can be inside or outside a curve, depending on the direction of the selected surface normal. A tangent constraint removes one degree of linear translation. Between a cylinder and a plane, it removes one degree of linear freedom and one degree of rotational freedom. | ||
Inside Positions the first selected part inside the second selected part at the tangent point. Supports user specified limits and resting position. | ||
Outside Positions the first selected part outside the second selected part at the tangent point. Outside tangency is the default solution. Supports user specified limits and resting position. | ||
An Insert constraint is a combination of a face-to-face mate constraint between planar faces and a mate constraint between the axes of the two components. The Insert constraint positions a bolt shank in a hole. The shank aligns with the hole and the bottom of the bolt head mates with the planar face. A rotational degree of freedom remains open. | ||
Opposed reverses the mate direction of the first selected component. Supports user specified limits and resting position. | ||
Aligned reverses the mate direction of the second selected component. Supports user specified limits and resting position. |
Show me how to set constraint limits
Selection
Selects geometry on two components to constrain together. You can specify one or more curves, planes, or points to define how features fit together. You can see the geometry to which a constraint is applied. A color bar on each selection button corresponds to the color of the selected geometry. If you make a mistake and want to select different geometry, click the appropriate selection command and reselect. | |
First Selection Selects curves, planes or points on the first component. To end the first selection, click Second Selection or the second face in the graphics window. The first selection is previewed in the same color as the select button color bar in the graphics window. | |
Second Selection Selects curves, planes, or points on the second component. The second selection is previewed in the same color as the select button color bar in the graphics window | |
Third Selection Available for Explicit Reference Vector angle constraint. Selects a face, linear edge, work plane, or work axis. The third selection is previewed in the same color as the select button color bar in the graphics window. | |
Pick Part First Limits the selectable geometry to a single component. Use when components are close to or partially obscure one another. Clear the check box to restore selection mode. |
Offset or Angle
Specifies distance by which constrained components are offset from one another.
Use to enter a value equal to a distance or angle that exists in the assembly, but when you do not know the offset or angle. Click the down arrow to measure the angle or distance between components, show dimensions of selected component, or enter a recently used value.
Specify positive or negative values. Default setting is zero. The first picked component determines the positive direction. Enter a negative number to reverse the offset or angle direction.
Show Preview
Shows effect of the constraint on the selected geometry. After both selections are made, underconstrained objects automatically move into constrained positions. Default setting is on. Clear the check box to turn preview off. If either component is adaptive, constraints are not previewed. |
Predict Offset and Orientation
If the Offset box is empty, inserts the offset and orientation for mate, flush, and angle constraints. The default setting is On. Clear the check box to set orientation and offset manually.
For an angle constraint, with an empty Offset box, the angle is measured and automatically applied. |
More
Sets the constraint name and options for assembly constraint limits. | |
Name | Creates a unique name for the constraint in the browser. You can enter a name or leave blank and a default name is automatically created. |
Limits | Use Offset As Resting Position Sets the offset value as the default position of a constraint with limits. For example, a constraint with a Maximum value of 50-mm, a Minimum of 0-mm and an Offset of 25-mm assumes the 25-mm position after a drag. Check the box to activate. Clear the check box to deactivate. |
Maximum Sets the maximum extent of constraint movement. Check the box to activate. Clear the check box to deactivate. The assigned value is retained when the check box is cleared. | |
Minimum Sets the minimum extent of constraint movement. Check the box to activate. Clear the check box to deactivate. The assigned value is retained when the check box is cleared. |
Assembly constraints - Motion tab
Motion constraints specify the intended motion between assembly components. Because they operate only on open degrees of freedom, they do not conflict with positional constraints, resize adaptive parts, or move grounded components.
Motion constraints are shown in the browser. When clicked or the cursor hovers over the browser entry, constrained components are highlighted in the graphics window.
The Drive Constraint command is not available for motion constraints. However, parts constrained by motion constraints can be indirectly driven according to the specified direction and ratio.
Access: | , and then click the Motion tab. |
Type and Solutions
Specifies the constraint type and illustrates the solution that shows the intended motion between selected components. May be applied between linear, planar, cylindrical, and conical elements. You can change constraint type when the dialog box is open during constraint placement or editing. When the cursor pauses over a component, an arrow shows the direction of the constraint. In the Solution box, click Forward or Reverse to change direction. | |
Rotation constraint specifies that the first selected part rotates in relation to another part using a specified ratio. Typically used for bearings, gears and pulleys. | |
Rotation-Translation constraint specifies that the first selected part rotates in relation to translation of another part using a specified distance. Typically used to show planar motion, such as a rack and pinion. |
Selection
Selects geometry on two components to constrain together. | |
First Selection Selects the first component. Select a planar face to specify the ratio or distance. Select a cylindrical face to calculate the ratio or distance. The selection is previewed in red in the graphics screen. To end the first selection, click Second Selection. | |
Second Selection Selects the second component. Select a cylindrical face on a rotational component or a linear edge on a translational component to calculate the ratio or distance. The selection is previewed in green in the graphics screen. To select different geometry on the first component, click First Selection and reselect. | |
Pick Part First Limits the selectable geometry to a single component. Use when components are close to or partially obscure one another. Clear the check box to restore selection mode. |
Ratio or Distance
Specifies the movement of the first selected component relative to the second selected component.
Ratio | For Rotation constraints, the ratio specifies how much the second selection rotates when the first selection rotates. For example, a value of 4.0 (4:1) rotates the second selection four units for every unit the first selection rotates. A value of 0.25 (1:4) rotates the second selection one unit for every four units the first selection rotates. The default value is 1.0 (1:1). If two cylindrical surfaces are selected, Autodesk Inventor computes and displays a default ratio that is relative to the radii of the two selections. |
Distance | For Rotation-Translation constraints, the distance specifies how much the second selection moves relative to one rotation of the first selection. For example, a value of 4.0 mm moves the second selection 4.0 mm for every complete rotation of the first selection. If the first selection is a cylindrical surface, Autodesk Inventor computes and displays a default distance that is the circumference of the first selection. NoteAlthough The ratio and distance parameters are used to specify the amount of movement for the second selection with respect to the first selection. However, the constraint is bidirectional. If the second selection is moved, the first selection moves by an inverse amount of either the ratio or distance, as appropriate to the constraint type. |
More
Sets the constraint name. | |
Name | Creates a unique name for the constraint in the browser. You can enter a name or leave blank and a default name is automatically created. |
Assembly constraints - Transitional tab
A transitional constraint specifies the intended relationship between (typically) a cylindrical part face and a contiguous set of faces on another part, such as a cam in a slot. A transitional constraint maintains contact between the faces as you slide the component along open degrees of freedom. |
Access: | , and then click the Transitional tab. |
Selections
Selects geometry on two components to constrain together. | |
First Selection (Moving Face) Selects the first component. | |
Second Selection (Transitional Face) Selects the second component. To select different geometry on the first component, click First Selection, and then reselect. | |
Pick Part First Limits the selectable geometry to a single component. Use when components are close to or partially obscure one another. Clear the check box to restore feature priority selection mode. |
Show Preview
Select the check box to preview the constraint to apply.
More
Sets the constraint name. | |
Name | Creates a unique name for the constraint in the browser. You can enter a name or leave blank and a default name is automatically created. |
Assembly constraints - Constraint Set tab
Constraint Set enables you to constrain two UCSs together. You can select UCS in part or assembly file.
Access: | , and then click the Constraint Set tab. |
Selections
Selects two UCSs to constrain together. | |
First UCS Selects the first UCS. | |
Second UCS Selects the second UCS. To select different first UCS, click First UCS, and then reselect. | |
Pick Part First Limits the selectable UCS to a single component. Use when UCSs are close to or partially obscure one another. Clear the check box to restore feature priority selection mode. |
Show Preview
Select the check box to preview the constraint to apply. Constraint set UCS to UCS results in three Mate constraints, created between the corresponding pairs of YZ, XZ, and XY planes.
More
Sets the constraint name. | |
Name | Creates a unique name for the constraint in the browser. You can enter a name or leave blank and a default name is automatically created. |
Drive assembly constraints
Simulates mechanical motion by driving a constraint through a sequence of steps. The component repositions sequentially by specified increments and a distance.
Access: | In the browser, right-click the assembly constraint and select Drive Constraint. |
Drive sequence settings
Set a precise amount of motion along a vector or about an axis. Use to simulate motion or test a range of motion for a constrained component. Click More to override default values for Increment and Repetitions. | |
Start | Sets start position of the offset or angle. Value can be entered, measured, or set to dimensioned value. Default value is the defined offset or angle. |
End | Sets end position of the offset or angle. Value can be entered, measured, or set to dimensioned value. Default is start value plus 10. |
Pause Delay | Sets delay between steps in seconds. Default is 0.0. |
Drive Adaptivity | Adapts components while maintaining the constraint relationship. |
Collision Detection | Drives the constrained assembly until a collision is detected. When an interference is detected, it is displayed and its constraint value shown. |
Increment | Amount of Value specifies that the increment is the value specified in the edit box. Default is 1.0. Total # of Steps divides the drive sequence into a specified number of equal steps. Edit box sets the value of each increment or the number of steps. Value can be measured, entered, or as dimensioned. |
Repetitions | Start/End drives the constraint from the start value to the end value and resets at the start value. Start/End/Start drives the constraint from the start value to the end value and then in reverse to the start value. Number of cycles completed within one repetition is dependent on the Edit Box value. Edit box sets the number of repetitions for Start/End and the number of cycles for Start/End/Start. Each movement is considered one cycle. |
Avi rate | Specifies the increments at which a "snapshot" is taken for inclusion as a frame in a recorded animation. |
Control buttons
Advance and reverse the drive sequence. The dialog box remains open while the drive sequence plays. Values can be changed any time the sequence is paused or stopped. | |
Forward drives the constraint forward. Not available unless both Start and End boxes have values. May resume forward play after a Stop. | |
Reverse drives the constraint in reverse. Not available unless both Start and End boxes have values. May resume reverse play after a Stop. | |
Stop temporarily stops the constraint drive sequence. Allows values to be edited and forward or reverse play to be resumed, advanced a step at a time, or advanced to beginning or end. | |
Go to Start returns the constraint to the starting value and resets the constraint driver. Not available unless the constraint driver has been run. | |
Single Step Reverse reverses the constraint driver one step in the sequence. Not available unless the drive sequence has been stopped. | |
Single Step Forward advances the constraint driver one step in the sequence. Not available unless the drive sequence has been stopped. | |
Go to End advances the constraint sequence to the end value. | |
Start recording begins capturing frames at the specified rate for inclusion in an animation. |
ASF Export Properties
Sets properties for saving the simulated mechanical motion of a driven constraint to an .asf, .wmv, or .avi file.
TipAfter you set export properties and close the ASF Export Properties dialog box, click Play in the Drive Constraint dialog box to create the recording.
Access: | In the browser, right-click an assembly constraint and select Drive Constraint. Then click Record in the Drive Constraint dialog box. Enter the file name in the Save As dialog box, and click Save. |
Profile | Displays a list of export profiles from which to select. See the information about the selected profile in the Profile Description field. If you select Custom Profile, you can set the Network Bandwidth and Image Size. |
Add Markers | Saves markers to the recorded file. |
Network Bandwidth | Specifies the network bandwidth. Select the bandwidth corresponding to your network connection. This option controls size of the output file and quality of the recording. |
Image Size | Specifies the size of the recorded window. |
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