(01-11-2023, 06:40 AM)feitang Wrote: Hi, there

I just wanna build a deformable rigid, like a barrel, as shown in this video https://youtu.be/-qaQETsXeWA (0:27s).

I didn't find this kind of information in the User Manual.

Thanks in advance.

Fei

(01-11-2023, 07:30 AM)josemendez Wrote: Hi,

Here's the relevant manual page:
http://obi.virtualmethodstudio.com/manual/6.3/shapematchingconstraints.html

This behavior is called plasticity. When deformed, plastic materials absorb part of the deformation into their rest shape. You can control the plastic behavior using plastic yield, creep and recovery parameters, see the above link for details.

kind regards,

(01-11-2023, 10:49 AM)feitang Wrote: Hi, Josemendaz,

Thanks for your quick reply. I have encountered another problem, and I am really confused about it. 
I set the ball and barrel with plastic yield 0.2, and build a hand model to grasp them. however, when I start the simulation, the ball and barrel immediately shrank, as the attached video shows.
I don't know how to fix this problem. Could you help me?

kind regards,
Fei

(01-11-2023, 11:30 AM)josemendez Wrote: Hi,

That means the plastic yield is too large, and the softbodies just crumple under their own weight.

Either spend more substeps on the simulation to make the softbodies more rigid, or reduce the plastic yield.

kind regards,

(01-11-2023, 11:56 AM)feitang Wrote: Hi, josemendez,

I set the plastic yield with 0, but the shrink also occurs. It is confused.

(01-11-2023, 12:31 PM)josemendez Wrote: Make sure the scale of your transform and the scale of your blueprint are correct. Otherwise the softbody will instantly shrink/expand upon being simulated, because the scale of visuals and physics don't match.

Check the RubberDragon sample scene for a setup example: the Dragon softbody object has a scale of 2 in all axis, the Dragon blueprint has a scale of 2 as well.

kind regards,

(01-11-2023, 01:54 PM)feitang Wrote: Very useful information! It does work! 

I encountered a new problem. I built a VR hand in the scene, which is a rigidbody, but how to make a collision with the softbody?
I put the rigid hand under the obi solver, and also added the obi collision to the VR hand, but it didn't work. 

look forward to your reply!

[attachment=1932 Wrote:[attachment=1933]josemendez pid='15040' dateline='1698843778']
Hi,

Make sure that:
- Collision constraints are globally enabled in your solver.
- Collision filters are properly set up. See: http://obi.virtualmethodstudio.com/manual/6.3/collisions.html

Note that Obi is a particle-based engine, which means that regular Unity collision callbacks (OnCollisionEnter/Exit, etc) and collider-based functionality (contact callbacks, raycasts, etc) don't work. Obi has its own collision detection pipeline, and its own collision callbacks / queries. See: http://obi.virtualmethodstudio.com/manual/6.3/scriptingcollisions.html
http://obi.virtualmethodstudio.com/manual/6.3/scriptingqueries.html

kind regards,

(01-11-2023, 02:51 PM)feitang Wrote: Hi, 

I carefully read the links you provided, and I think the two conditions are guaranteed, as shown in the attached figures. 
It is very confused why it doesn't work.