I have a POP and DOP network creating this effect of objects sliding on a surface.

There are some rendering problems with it.

1. DOPs seems to create a separate torus (grey; a passive RGD object, display geo switched off) that interferes with the propper, original torus (blue). The grey torus is not visible in the scene as its flag is switched of. Why does it render anyway?

2. The same grey torus starts to wriggle and shift position as the animation proceeds. How can I make it stable (it will eventually be an animated, deforming object like a character of some sort, but needs to act as a rigid body to interact with the particle geometry)

3. Particles render as tiny sphere. They should not render at all. How to make them invisible?

Well, I guess the grey torus just reacts to the particles hitting it. Both are RBD objects. Is there a way to make the torus not react to the particles (but the particles react to the torus)?

Hi,

I'm not entirely sure how you're reading the data back from DOPs for rendering so if you can post your hip file, we can take a look.

Well, I guess the grey torus just reacts to the particles hitting it. Both are RBD objects. Is there a way to make the torus not react to the particles (but the particles react to the torus)?

By default, the Merge DOP creates a “left affects right” collision relationship so you want to make sure the torus is connected to the left input. Alternatively, you can make the torus a static object instead.

A good way to set it up is to use the Static Object shelf tool which will set things up for you properly.

Cheers!
steven

Well, here's a file. I can't really work out where it goes wrong. Cranking up the RBD solver passes alleviates the probs a little but not completely. I ran out of ideas. :?

The object is animated to simulate a deforming mesh.

No ideas? :roll:

Hi there,

I wanted to tell you how I worked around the problem but finally found the actual problem.

The culprit is the activevalue1 DOP. It made rbdobject1 active so the jitter is from the collisons with the particle objects. All I did was to set the Group parameter of the activevalue1 DOP to exclude rbdobject1 & everything works as expected.
activevalue1 DOP's Group: * ^rbdobject1
Hope the above helps!

Cheers!
steven

Thanks Steve, absolutely brilliant! It works pretty nicely now.

Any hint on why the spherical RBDobject1 renders even though its flag and “Display Geometry” is off (and so invisible in the viewport but not in the render)?

I tried to work around the rendering problem by adding an objectmerge SOP in the source geometry and merging the DOP network, but that won't work. DOP import won't work properly either.

Is there something about rendering DOPs that I should know?

Now it's even stranger…