Contact — 3D Models
For 3D models, you can create a contact definition between two surfaces. When you click > 
Interface, Creo Simulate asks you to specify the two entities that you want to use.
Interface, Creo Simulate asks you to specify the two entities that you want to use.If you select two surfaces, Creo Simulate checks for the following on a pass or fail basis:
• The distance between the two surfaces must be less than one half the average of the length of the diagonals of the surfaces.
 | When creating contacts between surfaces, Structure limits the separation distance and angle between the two surfaces. If you are certain that the two surfaces will eventually contact and you want to work around this restriction, move the surfaces together, define the contact, and then move them apart again. |
• The surfaces must be no more than 36
off parallel at one point at minimum.
off parallel at one point at minimum.• A contact associated with the two selected surfaces cannot already exist.
Creo Simulate also checks to see if:
• the contact defined lies between two interpenetrating volumes.
• any curves in common between the two selected surfaces prevents the surfaces from moving completely apart during an analysis. If there are any such curves, a warning box appears and you should respond appropriately.
• you are attempting to create a contact on a surface that is on the boundary of two volumes. Applying a contact to this surface allows the volumes to separate.
If you split a surface that two volumes share, you must place contacts on all split surfaces to allow the volumes to separate.
For each valid pair of surfaces, Creo Simulate places a contact icon at the point where the surfaces are closest to each other, oriented along the point of closest approach.