I wonder if Brethren has an update on getting all the source files from Otto?

This pack contains some objects for the Dark Engine which use replaceable textures, allowing for many different uses. Just extract into your working Thief or Thief 2 install folder and create a suitable object in game, and then change the Shape > Model name to one of the models below. Then set the textures via the Shape > TxtRepl r0, r1, or r2 properties, which require the full relative path, e.g. "obj/txt16/frame1".

res_cube:
A reskinnable cube with replace0, replace1 and replace2 on opposite faces, and the single most useful object I've ever made despite its simplicity. It can be resized however you need and also flattened and used as a decal on a wall or floor. Since with terrain (fam) textures you're limited to powers of 2 for the dimensions, this allows you to map a single texture onto any size face you want. Just a few examples include flattening completely and using on a wall as a sign, poster, writing or graffiti, or on the floor as a bloodstain, scratches by a secret door, or layer of dirt or grime; flattening mostly and applying a rug texture to the top and a solid colour to the sides and using as an odd-sized rug; texturing however you wish to use as any rectangular solid object, such as a cabinet, wall, box, etc. I also make heavy use of the res_cube as window objects which use textures with partial transparency.

I generally create an instance of Decorative for most non-physics uses, and for cases where a physics model is needed (rug, window, cabinet) I either add the physics properties manually to the DEcorative, or I instantiate a suitable object which already has physics properties. Remember for physics objects you need to set the Physics > Model > Dimensions appropriately, and also add the appropriate Material metaproperty.

res_scroll:
A version of the EP scroll object with both top and bottom textures made replaceable. Included are scroll1.png and scroll2.gif as sample textures, but you can customize particularly the top texture to make the object look like a map, blueprint, secret formula, newspaper or whatever suits your needs.

res_poster:
A simple flat object with a single replaceable texture, this differs slightly from a flattened res_cube in that the texture is mirrored when viewed from the back side. This allows it to be used, for example, as a window with lettering on it which should be reversed when viewed from the other side. It can also be used in many of the ways described above under res_cube for flat decals, without requiring flattening.

res_pnth and res_pntv:
Horizontal and vertical painting objects with replaceable canvas and frame. Use TxtRepl r0 for the canvas, and TxtRepl r1 for the frame. Six frame textures are included in obj/txt16, but feel free to make your own.

Textures provided (in obj/txt16)
blank: A blank texture (a single pixel set to palette index 0) which can be used to make a face of the res_cube fully transparent, e.g. the untextured sides of a window.
frame1-frame6: Sample frame textures for the paintings.
scroll1, scroll2: Sample top (with writing) and bottom (blank) textures for the scroll. You could use scroll2 on both sides for a blank parchment.