How to change the shape of a mesh in create?

Can a mesh be cut or reshaped in omniverse without the help of other 3D applications.

Hello @Wayne1407! We currently do not have tools in Create that allow for the detailed mesh manipulation you are requesting. I will send a Feature Request ticket over to the dev team.

Have you tried using our Blender branch in the Omniverse Launcher? It’s and awesome 3D manipulation tool and it’s free!

A feature request ticket was created from this post. OM-78719: How to change the shape of a mesh in create?

Thank you! I’ll give it a try.

Hi, are there any documentations about collision detect? I want to realize that if it’s detected then destroy that cube. Maybe this can achieve the same results in visual appearance.

Hi Wayne.

There are a few ways to detect and act upon collisions. Can you give me some details on exactly what it is you want to do?

The scene in this picture was made in Unity. The coal is a block set of small textured cubes each with colliders. Th drum then uses python scripts to do collision detect and if its tagged coal then destroy that cube. Can it be easy in omniverse? Or can it be made by the Animation Graph?

I think that for this application I would investigate the use of the Blast destruction extension.

If you are familiar with scripting, collision apart from Blast can be detected via Triggers in conjunction with a script file. Select a mesh, add collision, add trigger, and enter a path to the enter and leave scripts.

If you are familiar with Action Graph, a simpler method may be to use a trigger as above, then add the Trigger State property, and in the Action Graph use the Get Prim Relationship node referencing the trigger mesh to return an array of all intersecting bodies on tick. Feed the output of a For Each loop to a Switch On Token node to trigger whatever actions you like for each intersecting body.

Let me know if these instructions aren’t clear.

Addendum: The relationship to use in the Get Prim Relationship node is “physxTrigger:triggeredCollisions.”

Hi, maybe there is a little problem for me to know how the Trigger in Physix work. I just create a scene with two cubes and the ground, all of which with collision, and the /World/Cube is added with a Trigger. Then I set the graph just as you showed in the picture. But when the Cube fall down, it just falls through the Cube_01 and the ground, I don’t know why the trigger does not work. There is no documentation about the Trigger using I can find.

By the way, when I was using the Contact Reporter, it couldn’t show in the Console, was I missing something important?

The mesh with the trigger must be either static, as in just a collider, or a rigid body with kinematic enabled. It cannot be both a trigger and have physics motion.

Try placing your trigger cube under the other body and check the “Kinematic Enabled” box under the rigid body properties.

For your application, you would make the cutter part of the machine a rigid body with kinematic enabled, and it would report what it is intersecting in the graph. You can then take the output of the for each loop and hide the original object and unhide the replacement objects.

Hi, can you share the .usd in this scene? I still can’t achieve the goal…
questionwithtrigger.usd (11.1 KB)
Here is the .usd that I created, and nothing changed in console or in the viewer.

You’re missing three items, Wayne.

First, in order for the cube to report its intersections to the prim relationship node you have to add Trigger State to its properties.

Second, you have to add the paths to your sphere prims to the “Switch On Token” node, like so.

Third, your “Write Prim Material” nodes are all referencing the cube. They should each reference the same sphere as the “Switch On Token” execution path they are linked to.

After making those changes, this is the result I get with your stage.

Thank you for your detailed explanations! I totally understood how to use Physics_Trigger, I had misunderstood the using of Switch_On Token before, it is really convenient to create the scene in omniverse!

No problem, glad it worked for you!

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