Can you get a sphere to follow a cached bgeo object?

[Xsiv]

I am using use cached bgeo files and want them to be static RDB objects. I can't seem to get them to interact with much.

So - BBox sphere around the cached files.

I have been manually animating a sphere (like a BBox) around the objects to crash into other objects.

I do not want to have to do this over and over again.

I am looking for a way to have the sphere object follow the cached data. There are no channels to use for expressions. I need something like a rivet from Maya.

Any suggestions - either getting the GeoCached files to act as better RBD or parenting a sphere to this bgeo cached file?

Thanks

Chris

[anim]

something like rivet from Maya? hmmm, could it be Rivet Object in Houdini?

you can use it as it is to reference any point or group of points

but here is something you can do if you want to get exact bounding sphere:

append Sphere SOP to File SOP which is importing cached sequence

this will create bounding sphere over the geometry, it will move with it, but it is still a deformation since it is at SOP level and that is not good for RBDs if not needed

so at scene level create Rivet Object, put path to sphere SOP to Rivet Geometry parameter

and 0 as a point group (since Sphere by default is a primitive, rivet will follow it's center)

parent whatever you want to Rivet Object and use that as RBD

also look at Extract Transform Object, very useful if you need to get transform of cached geo, just feed static geo (first frame) as Source Geometry and sequence as Destination Geometry, then parent any object to it (maybe the same first frame of the sequence)

[Xsiv]

Fantastic! That is what I needed to get the geometry to follow the animation. Thank you.

Now I hooked things up and set the sphere up as a RBD Object.

The sphere flies right through my wall/sign/flat plane, without colliding to it.

Am I missing something here?

Why does the sphere go through the plane? It is in the DOP network.

I did change the sphere into a Polygonal Mesh and turn on "Use Deforming Geometry" in the DOP network.

I have both the rivet method and the sphere as a bounding sphere to the animated object going. No luck with any interaction.

Any suggestions?

Chris

[anim]

don't check use deforming geometry if you are using rivet to pass transformations to undeforming sphere

check if you have mutual collisions in Merge DOP if your sphere is on the right side or just add it to static RBD to left side and set merge collision mode to Left Inputs Affects Right

or look at example file just for concept

collision.hip

[Xsiv]

Awesome.

I thought that my animated flying debris piece had to be a RBD object and turning it off.

Having it on the static side of the solver makes sense, as it follows animation.

Thank you

Chris