Here is the first part of my current character workflow for custom stylized Metahumans - I developed it for the short film I’m working on (‘Raj Pai, Gentleman Spy’). This part prepares a Metahuman head based on an unrigged stylized basemesh, and then textures it in a painterly style using Midjourney to speed things up.
This workflow owes a lot to @JoeRaasch and @PIXXO3D. Joe’s workflow uses Houdini, and mine uses Wrap3, but I’m using his approach and principles. PIXXO’s projection mapping workflow is the best I’ve found anywhere and he explains it in more detail than I do.
My workflow uses Blender, Unreal Engine + the MeshMorpher plugin, Wrap3, Photoshop Beta and Midjourney.
Objective 1: A rigged Metahuman head that retains the fully pushed shape of a stylized base mesh. I start with an unrigged, untextured stylized base mesh that includes head and body (attached together).
1a. Run the stylized base mesh through Unreal’s Mesh-to-Metahuman process. Only 1 promoted frame really required in the Neutral Pose. Make sure to use the Data-driven Eyes option to get the eye position right. Mesh-to-Metahuman is necessary to get the facial bones positioned correctly, but it rarely replicates the stylization perfectly. I use a corrective morph to fix this.
1b. Prepare resulting Metahuman head as corrective morph source. Since my objective is a stylized look, I disable all sections except 0,1,3,4 (which are the face, teeth, and both eyes. I also only use LOD0, so I set the Number of LODs to 0 and Apply Changes. Use MeshMorpher to export as OBJs: a welded version of the mesh (this will be the corrective morph source) and an unwelded version (this will be the high poly mesh for texturing later).
1c. Align stylized mesh eyes and prepare as corrective morph target. Import the welded mesh and the original stylized basemesh, and align the base mesh to the welded mesh, taking care to line up the eyes as closely as possible.
1d. Wrap Metahuman head around stylized mesh and export new mesh. Try to use the Wrapping node for this vs. Fastwrapping - better results. Since the meshes are pretty similar, I rarely have to put in any alignment points, which makes this really fast.
1e. Create morph target using newly wrapped mesh. Set up new morph target in MeshMorpher using Create from Mesh Files.
1f. Test new morph target with animation sequence. You need the face to move in extreme ways to test the new morph target - I set a specific animation to use in the Preview Settings.
Objective 2: A stylized, painterly base color texture layer for the newly rigged custom Metahuman head. The standard Metahuman materials are much too photorealistic to work well with the stylized mesh shapes.
2a. Decimate wrapped mesh and place seam for UV unwrapping
I’m going to use projection mapping to speed up the texturing here, so a standard Metahuman LOD0 head mesh is much too high poly to do that easily. The seam is placed in the back of the head since that is usually less visible.
2b. Prepare UV Maps for projection mapping. I prepare two UV Maps on the newly decimated mesh - one called Front Projection for use in the projection mapping, and another called Main Map Output, to be used as a clean non-overlapping output texture map.
2c. Use orthographic view as input image to Midjourney. This is optional but I find it helpful - an input image helps Midjourney give you output that roughly follows the shape of your mesh. Feel free to play with the prompts - this is what I used for this example: “an orthographic front view avatar character portrait gouache painting of a bald chubby english politician, symmetrical, colorful, handpainted, painterly, stylized, graphic novel, natural lighting, overcast --niji 5 --s 250”
2d. Remove highlights, shadows and hard outlines with Healing Brush and Smudge. Since this will be a Base Color texture, we want minimal harsh lines and don’t yet want to bake lighting into the texture. I use a wet media brush on the Smudge tool to get some nice paint strokes and texture into the colors.
2e. Adjust mesh with Grab tool to clean up projection mapping. I do each side of the face separately here too to introduce some naturalistic imperfections and irregularity - perfect symmetry is boring.
2f. Use Clone Stamp to transfer texture to a new UV Map. This is to get a clean output texture using a non-overlapping UV Map - as you Clone Stamp onto the mesh, the texture appears on the Main Map Output image, which can then be saved out to a PNG file.
2g. Use TransferTexture to map onto high poly version of the wrapped mesh. Fastwrapping usually works fine here vs. the Wrapping node. Here I wrap the texture map I have just put on the decimated low poly head mesh onto the high poly wrapped mesh I used as a corrective morph target.
2h. Test new texture with animation sequence
2i. Further cleanup with Healing Brush and Smudge. I also add more texture here with the Smudge brush, and imperfections, scars, scratches, etc.
Music: Spy - Spring Gang
Негізгі бет Custom Stylized Metahuman Heads with Midjourney-assisted Texturing : Character Workflow Part 1
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