Engineering Talk - DCS's Blog on Quality and Engineering

Constraints in 3DCS - How to Use CAD Constraints in 3DCS Tolerance Analysis

 

 

This tutorial will cover DVTI_FixedJnt Fixed Constraints and DVTI_FixTogetherConst Fix Together Constraints to illustrate common constraints you can expect to use. The Fixed Constraint holds all of the parts in the Move Parts list in their current location and orientation. Any moves that list one of the parts as the "object" will force the "target" part to move instead. The Fix Together Constraint holds all of the parts in the Move Parts list perfectly rigid relative to one another. If one of the parts is moved then the other parts will move with it. Additional constraints include Coincidence, Contact, Offset, and Angle.

DVTI_FixedJnt Fixed Constraints

  • Create a Fixed Constraint for the Base part.
  • Ensure no part is currently selected.
  • On the DCS Mechanical toolbar, expand the Constraints toolbar and select DVTI_FixedJnt Fixed Constraint.
  • Select the top product, 3DCS_Mechanical_Engine, in the Navigation Tree.
  • Name the move "Fix_Base" and give it a Description of "locked location and orientation".
  • Select the Base part in the graphics window for Part under the Move Parts tab.
  • Click [OK] to create the move.

 

MECHmove_fix

Mech_Move_Fixed

DVTI_FixTogetherConstFix Together Constraint

  • Create a Fix Together Constraint for the Base and Block parts.
  • On the DCS Mechanical toolbar, expand the Constraints toolbar and select DVTI_FixTogetherConst Fix Together Constraint.
  • Select the top product, 3DCS_Mechanical_Engine, in the Navigation Tree.
  • Name the move "Base_Block_FixTogether" and give it a Description of "parts rigid with respect to each other".
  • Select the Base and the Block parts in the graphics window. They will be listed as Parts under the Move Parts tab.
  • Click [OK] to create.

 

MECHmove_fixtogetherMech_Move_FixedTogether

 

  • Select the Share Icon Share Menu button in the top right corner and select [Save]. Or expand the save menu and select [Save with Options] and name the file "3DCS_Mech_Engine_Lesson3".

Conclusions

Constraints are moves.  They are routines that define a parts location and/or orientation in space or relative to other parts. Common constraints, as illustrated in this tutorial, include fixing a part's location in space or in relation to another part.

Topics: PTC Creo 3DCS Creo Siemens NX Webinar CATIA V6 Tolerance Analysis 3DCS CATIA