obj2tmd

obj2tmd converts a Wavefront OBJ model, which Blender and most 3D programs export, into a TMD, the model format GsSortObject4 draws, laid out as format/tmd describes.

$ png2tim --at 640,0 --clut 0,480 stone.png
$ obj2tmd --scale 64 cube.obj
created "cube.TMD": 344 bytes
  object 0 "cube": 8 vertices, 6 normals, 6 polygons

Each o in the file becomes an object of the TMD, which a program links with GsLinkObject4, or a TMD's Link, by its number from 0. The axes are turned from the OBJ's, Y up with the camera looking down -Z, to the console's, Y down and Z away from the camera, and the corners of each face reversed, since the console draws the side of a polygon whose corners go clockwise on the screen and an OBJ's go anticlockwise. Faces of more than four corners are split into triangles. Coordinates are multiplied by --scale and rounded to the 16-bit integers a TMD holds.

Faces are lit by the library, flat with a normal worked out from each face, or with --smooth gouraud with the file's vertex normals. --unlit draws colours and textures as they are. A material's Kd colours an untextured face, and one with map_Kd is textured from a TIM made with png2tim: the map's name with the extension .TIM, beside the MTL file or in the directory --textures names, the program's data say, under the map's name or the disc's form of it (capitals, underscores, eight characters), which is how the playground names what it converts. The TIM says where the texture sits in video memory, so the program loads the same TIM; texture coordinates are relative to the image, and the page offset is added.

Sony's FAQ lists what the Net Yaroze library does not draw from a TMD: lines, sprites, double-sided polygons and gouraud-shaded quads without a texture. --both makes each face two faces, back to back, instead of one double-sided one. The tests write the square example's cube as an OBJ and check that it converts back to the same faces.