Coordinates of Colliding Objects

I want to know the X,Y,Z co-ordinates of the point at which two 3D
objects collide. Seems like the collision detection feature must know
this, but I can't figure out how to display it. Anybody know?

 

It's not that easy as colliding bodies might have multiple contact points,
even an infinity (contact curve) and even a squared infinity (contact
surfaces).
For a specific case (I guess yours is one), you have 2 approaches:
1) add some geometry (planes, axes, points) to retrieve the contact point(s)
by construction
3) use a macro. I did one for a customer
(http://www.dynabits.com/products/contact/index.htm) that builds coordinates
for CAM based on tool/part contact detection. While writing that one, I
discovered the collision detection used by SolidWorks in interactive mode, I
found it was very imprecise. I had to, well, take a different approach to
reach the micron precision the customer needed.

Tell me if you need more help.

 

Yes, that's exactly how my "contact" macro works ;-)
Maybe the animation on http://www.dynabits.com/products/contact/index.htm
isn't clear enough, but for each angle of the blue part, it adjusts the
dimension to the contact with the yellow mill (which has a round profile).

The computation takes less than 1 second per point to achieve a (sub-)
micron precision.
I trust SW for using a collision detection algorithm that is both accurate
and fast. I guess they already use some optimization techniques you
describe, Cliff.

Now, locating the position of the contact isn't that easy in some cases.
Consider a 3-legged chair "colliding" the floor.
It might have 1, 2 or 3 contacts depending on a tiny variation of the angles
of the chair with respect to vertical.
And with 4 legs, you'll know how rigid a 3d model can be... The main think
is to define carefully (with tolerances) what you call a contact in your
application, and depending on the answer, you might need FEA...

Philippe Guglielmetti - www.dynabits.com

 

Thanks all for the info. I'm a SW newbie, and I was hoping I'd
overlooked a pop-up that would provide the co-ordinates of the point
of collision/interference. Oh well, maybe SW2006! Meanwhile, I'll be
wrestling with axis, planes, and the measuring tool...

 

Jota

Is this what you mean by "wrestling"? :

If the contact occurs within a single face on each part, you can get a good
idea of the location by moving them apart a tiny amount and then clicking on
the faces and "Measure" will draw a yellow line between the points of
closest approach. Getting the coordinates is not trivial, unless you only
need an approximation. Maybe constraining a 3D point to lie on each face,
and driving it from dimensions from your construction axes, and moving it
(initially make dimensions driven and drag, latterly switch to driving and
jog into position visually)