View Full Version : 3d cutaway animation

09 September 2002, 08:11 AM
how would you render an animation of an object with parts of it cutaway to show detail. The object is a industrial bearing, and I need to show the internal seals and cavities while parts are rotating. The main bearing housing is no problem, I just cut a section and gave it an invisible surface. The shaft I can leave solid. The problem is with some of the internal bushes that rotate with the main shaft.

Is there some way to use a cube as an object intersection on a solid model in layout? So the area covered by the cube would disappear?

An ideas would be appreciated. Deadling is looming on wendesday.

09 September 2002, 08:32 AM
Model the thing, in Modeler, in layers. Use the Boolean/Drill tools to cut the section out that you want.

09 September 2002, 08:52 AM
Is this (see attachment) an effect that u looking for ?
If yes - here is the steps:
1. In modeler make cube or cylinder in spline in the background layer - with this object u going to cut your object...
2. Use Solid Drill in case of using cube or other solid object... Use Drill in case of using spline or polygon...
3. In the Drill/Solid Drill use stencil option, and give some new name for surface.
4 After drill, go to Surface editor and copy surface of your object to newly created (with drill) surface.
5. Make some envelope on transparency channel.
6. In Layout adjust this envelope to your animation, and SAVE object. If u don't save your object u will loose your envelope changing...

09 September 2002, 07:13 PM
Thanks for the replies.

Eugeny, nice work!

I need a different effect though. I have attached a pic of what the client has in mind. The shaft is transparent here, but I will make it solid since I need to show how liquid flows over the bearing surface and cools the seal faces (which is another challenge in itself)

CIM, if I cut a quarter of the round bush away, in frame 1 it will be fine, but as the thing rotates the cutaway section will not be aligned anymore. I need a way to have a constant static cutaway on a rotating object.

09 September 2002, 07:27 PM
If i understand u correctly u need to start with transparent section of object and end up with solid one, right?
So my technique will work for u...
Here is ( ) how this work (sorry for m blur - this stuff still not finished)

09 September 2002, 07:32 PM
Check out Animated Boolean, it'll do exactly what you want:

here (

09 September 2002, 08:58 PM
animated boolean does the job, and then some :)

thanks a million for your help mattoo, I may even get some sleep tonight

I downloaded your animation Eugeny, and I think your technique will work for another section I was wondering about. It works well, thanks

09 September 2002, 08:15 AM
ever thought of planar clipmapping ? i mean you should try this out i think it works. just made a little sketch to show what i mean

09 September 2002, 11:09 AM
mrwyatt, thanks for going to so much trouble, I appreciate it. I tried what you suggested, and it works fine, except for where the plane clips the object. At that point the object has no closing polygon on the disected face and you can see into the object and view the inner surfaces. Does this normally happen or did I miss something?

09 September 2002, 11:20 AM
Yup, that should happen which is why I didn't suggest it.

Sadly what you're wanting to do is something that's a lot easier in apps that have a combined workflow such as Max or Maya where you could animate a boolean object to cut away the pieces that you want, when you want and get a direct feedback.

You're best bet is the Animated boolean, which is the same idea, just a bit disjointed because you have to go back and forth between Layout and Modeler. Just make sure you've got a nice clean mesh and as few open edges as possible and the boolean should be fine.

09 September 2002, 11:21 AM
dang, didnīt thought of that. yup this happens when you clip polys. you make them invisible so you get holes in your mesh. thatīs the only problem i think but i donīt know how to fix it. sorry.

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