Debugging and offline/static analysis.
I had this sorted out a while ago to code a J3D loader replacement with something more modern (GLTF).
+0x294 was an offset to the runtime structure indeed (S3DModel).
The model/mesh/subset data size is 0x60 bytes.
The render state change that wrapped that 2nd drawprimup was, on the other hand:
SetRenderState(D3DRS_ZFUNC, D3DCMP_NEVER);
DPUP();
SetRenderState(D3DRS_ZFUNC, D3DCMP_LESS);
SetRenderState(D3DRS_ZENABLE, TRUE);
Maybe for some decals rendering, I don't know.
