john patterson


About Me

VFX Artist
United States

NYC Dynamics guy


Recent Forum Posts

VAT RBD motion detection in shader? Jan. 26, 2022, 10:13 a.m.

I need to hide RBD chunks that are moving. I am trying to us the MF_Rigid to do it. It seems like I ought to be able to sample the VAT position UV texture at the top and bottom of a single column to see if the chunks start and end positions are different. I have tried wiring it up, but it's not working. Does anyone have a setup they could share? I tried duplicating the MF_Rigid that is provided by SESI, so that I have 2 of them in my material. I pass 0.0 into the time input of the second MF_Rigid node. I then compare the WorldPositionOffset outputs from both MF_Rigid nodes. This seems to give me distance from the object's pivot, not distance travelled over the whole simulation.

VAT 3 slerp with object level transforms Nov. 30, 2021, 5:07 p.m.

Did the SLERP transforms get ironed out? If not, are VAT 2.0 and VAT 3.0 both available in Houdini 19? We're using H18.5 and Unreal 4.27 now, and looking to install the latest Houdini Engine plugin, which looks like it's intended to be used with H19. Is it safe to upgrade to H19 and the latest Houdini Engine?

get smoothing_group info from Unreal to Houdini via HDA Nov. 24, 2021, 10:21 a.m.

How can I get smoothing group info from Unreal into a Houdini HDA? I see many unreal_material_paramter_* attributes in Houdini, but not the unreal_face_smoothing_mask attribute listed here: Your text to link here... []

Is there something special I have to do in Unreal to make the data come through? I am processing models from Unreal in an HDA and then bringing them back into Unreal. It's not enough to set a cusp angle on a Houdini normal node. I need to reproduce what is in Unreal already. This is for VAT RBD stuff, so when the original mesh is swapped for the RBD mesh the different normals are instantly a problem.

I don't have any smoothing group info. It would be fun to figure out a way to recreate the vertex splitting that UE does in the HDA so I can output geo that looks like the original, but for now the normal node will have to do.