texturing an animated mesh, sticking stroke / texture to UV

[thomas24943017brqa]

Hi, I am texturing a complex asset made of multiple meshes that are animated. It is like a transformerss, first frame of the animation it is a car and on the last frame parts have moved and rotate and it is now a robot. 
My issue is that I need to paint details on both the first and last frame of the animation (like a battle damage that spread accross multiple parts in the car form and other battle damage that spread across multiple part in the robot form). Unfortunatly "Substance 3D Painter saves its data in 3D in world space to keep everything non destructive. That means that when reimporting a mesh, Substance 3D Painter tries to paint where the mesh was before the reimport, it has no way to know where some pieces could have moved", which means Substance painter can't reproject the texture on the correct location. Is there a way to make Substance Painter use the 2D UV instead of the 3D space ? 

Here is a simple version of the issue I am facing. as you can see the stroke have moved when I imported the same mesh but on a different state (location and rotation are different for the lid).

Here the set-up I made to try to solve my issue:

• I have 3 meshes with the same material unwraped using UDIM so 1 UDIM tile for the box and another tile for the lid . The 8 little cubes that serve as a bounding box are also unwrapped on the UDIM.
• I export the first frame of my animation as an FBX, I export the last frame of the animation as an FBX
• in substance painter I import the first frame FBX, paint on the 3D view a red and a green mark (the red mark spread across the two meshes).
• put my paint layer in a folder and create a smart material 
• go to edit > Project Configuration > File and select my last frame FBX (check preserve stroke position on mesh but also try with that parameter unchecked) 

Here is my more complex project with the strokes not sticking to UV


A workaround would be to export the texture I painted on the car state of my project, import robot state FBX and keep working on it, but I would loose the ability to control precisely my texture thanks to the multiple layers and mask used on complex projects. I also know that If I had painted on the 2D UV then the stroke would keep their location between the car and the robot state, but depending on the seams it is not possible.

Is there a way to keep the strokes pinned to their location on the 2D UV so I can import my mesh in its robot state and continue working on my texture ?  If not it would be an interesting feature for the future versions of SP

[Cyril Dellenbach · Accepted solution]

Hello @thomas24943017brqa,

Thanks for the message.

Unfortunately, I cannot tell you much more. You explained pretty well how our reprojection works and its limitation.

For me, there is two workarounds and those are the ones you already talked about:

1. You could export your textures from the first project and reimport them into the new project, but as you said, you'll lose the ability to tweak the layers.

2. You could paint everything in the 2D view, forcing the reprojection trough the UVs, but this is tedious and sometimes not possible depending on the UVs.

Substance 3D Painter isn't really made for this type of workflow, but we know the ability to reproject the work depending on the UVs is a very expected feature from the artists and let me share this thread to our team as a reminder.

Have fun with your project and best regards,

[thomas24943017brqa]

Sure, you can share it, it would be nice to see this feature in the future
! Thanks for the information anyway.