SaOk
Working for me now in 18.5.449, while not yet in production build. Just separated the _3d_hidden_primitives and merged back before export. Could now import CC3 to Houdini, combine material slots with vertex colors and export to UE4. Blendshapes appearing to make faces. Thanks for the fix.

Would it be possible for you to show us the final setup you created for this to work?
Last december I struggled for this to work and ended up working with the oldschool bone setup, just for the blendshapes, as a temporary fix. I was working with mocapped characters in unreal (body and face) and wanted to use the kinefx tools to set it all up. but that gave me a lot of troubles when trying to export the blendshapes. I am glad you got this working and would like to set it up at my side aswell.

Hey @Simon van den Broek can you upload your network? We are using it in production with 18.5.462 and it works very well. Example HIP file posted by edward shows exactly how to set it up and export it. Maybe your ROP SOP is after characterblendshape SOP, where it should be exporting data before going through characterblendshape.

@hektor, My Apollogies for the late reply!! I tried it again back then and got it working! thanks everyone and especially Edward!!

Now I would like to play around with corrective blendshapes aswell has anyone tried this before?

With Houdini's old ROP FBX Output, I can "force blend shapes", which is the only way I've been able to get them to show up in UE4 at all. The problem with that is UE recognizes the blend shapes to be the root bone, the only bone, so the fully rigged (actual) character skeleton won't work with the blend-shaped (single-bone) mesh. I can either get my blend shapes, or I can get my rigged character, but not both. I tried to integrate the included HIP setup for the new "character blend shapes" node with the new "ROP fbx character output" node, but I cannot for the life of me make that work. Someone please help my team is counting on me!

wijobu
With Houdini's old ROP FBX Output, I can "force blend shapes", which is the only way I've been able to get them to show up in UE4 at all. The problem with that is UE recognizes the blend shapes to be the root bone, the only bone, so the fully rigged (actual) character skeleton won't work with the blend-shaped (single-bone) mesh. I can either get my blend shapes, or I can get my rigged character, but not both. I tried to integrate the included HIP setup for the new "character blend shapes" node with the new "ROP fbx character output" node, but I cannot for the life of me make that work. Someone please help my team is counting on me!

Hi Wijobu, is there any update about the "must select 1 of 2" problem?

I cannot even get the blendshape in bone deform node in 18.5.563..

wijobu
With Houdini's old ROP FBX Output, I can "force blend shapes", which is the only way I've been able to get them to show up in UE4 at all. The problem with that is UE recognizes the blend shapes to be the root bone, the only bone, so the fully rigged (actual) character skeleton won't work with the blend-shaped (single-bone) mesh. I can either get my blend shapes, or I can get my rigged character, but not both. I tried to integrate the included HIP setup for the new "character blend shapes" node with the new "ROP fbx character output" node, but I cannot for the life of me make that work. Someone please help my team is counting on me!

Hi Wijobu, is there any update about the "must select 1 of 2" problem?

I cannot even get the blendshape in bone deform node in 18.5.563..

goose7
I cannot even get the blendshape in bone deform node in 18.5.563..

If your FBX has blendshapes, then it should work. You need to insert a Character Blend Shapes node before the Bone Deform though because that's the node that will deform them, not Bone Deform (which only does the skin deformation).

goose7
Hi Wijobu, is there any update about the "must select 1 of 2" problem?

The problem "must select 1 of 2" is solved. Not in the perfect way though, but it works in Unreal. So, when exporting different animation clips you should (for now) always use the workflow from this post [www.sidefx.com] hip file, basically creating the blendshapes as packed prims with the attributes. Hopefully this will be addressed in the next versions. I had asked to address just the exporting the animation with the rop_fbxanimatonoutput because for now it just exports the joint transforms with the skeleton but it doesn't save the animation data of the shapes weights, not that I was able to extract in the Unreal. So, I am using it in the same way, as in the hip file, if I have more clips, I just export the whole character with the rop_fbxcharacteroutput with the new animation in the third input, but when I am importing the asset in Unreal, I don't export the skin. That way you have your project still under control that you don't import a lot of meshes but just the animation data in Unreal. I am just writing this here if anyone stumbles on this forum like I did yesterday. The Sidefx took my request for the rop_fbxanimationoutput and hopefully this issue can also be addressed in some future builds.

Just tried this myself (hoping to be able to export blendshape and joint anim data via rop_fbxanimationoutput alone) blendshapes didn't make it into UE and an fbxanimimport back into houdini no longer has the blendshape detail attributes that drove the characterblendshapes anim input prior to export.

Is is possible to keep the blendshape and joint anim data together, separate from the character export imported without any anim data? (H19.0.455)

Also not having much success telling the UE FBX import options to just read in the animation from the fbxcharacterouput file without importing new skelmesh/skel/geo/weights etc... as suggested above.

For future reference, I updated the example edward provided with H19.5 nodes. I've also tested the exported .fbx in both Blender and Unity and it works.

If you're in 19.5 (or 19.0 for that matter), use the Character Blendshapes Add SOP [www.sidefx.com]. See also the blendshapes page [www.sidefx.com] for info.

Thank you edward and kodra. With the help of your example files, I am able to export blendshapes to the GLB file format using ROP GLTF Character Output.

I encountered one important problem, where it seems, that the normals are not present in the blendshapes of my GLB files. I created and attached an example, where I blend between a cube and a sphere to better illustrate the problem:

When looking at the exported GLB file in a text editor, the base mesh has got all the exported attributes like "POSITION" , "NORMAL", "TEXCOORD", ... But for the blendshape (morph "target" inside the GLB file), there is only the "POSITION" attribute present.

When previewing the blendshape of my GLB file in a GLTF viewer, like here [gltf-viewer.donmccurdy.com], then you can see the shading problem, which the missing normals of the blendshape create.

The desired outcome would be the preview inside Houdini where the "P" and "N" attributes are both blended, creating the desired transition of the normals when transitioning from the base mesh to the blendshape.

Am I missing something in my GLB export setup?

This could be an oversight, best thing to do is to a log a bug. (eg. using Support > Report a bug/RFE at the top of the website).

I agree. Looks like a bug.

Thank you for the confirmation. I filed a BUG.