I've noticed there doesn't seem to be much in the way of shrubbery in this game, and as any fan of monty python fan can attest, shrubbery is of critical importance 
We have quite a few models/prefabs, but most of these are low quality. We're always happy for more to be made and Tilli is currently polishing up the +forest RMA, so he could probably incorporate them. Load up UFORadiant and check out the prefabs to see what we've already got. Burningwell.org has a lot of really great foliage source images to use. I've had them saved on my hard drive with the intention to do something with them for ages.
When I was modding fallout 3 I did a greenworld total conversion mod that included many types of grass and shrub, generally they are made of a .png image which is mostly transparent with just the grass or shrub visible, that image is then placed upright by attaching it to an invisible model in a star or cross shape, so that the grass is visible from multiple angles.
The main difference with UFO:AI is that the most common view is from the top, so simply having side-view of shrubbery on vertical planes doesn't work all that well. The best shrubbery we have (IMHO) is the fern2, which looks good from the top and the sides, but of course all vegetation will be different.
I seem to remember hearing that line of sight through shrubs hadn't been worked out yet, is that all thats keeping us from making shrubs? Is it possible to make objects walk-through-able? If so, would you guys like me to work on some grass profile images? Or should I start coding up the shrub line of sight fix?
If you can work out line of sight that will be a major milestone in the development of the battlescape. But as I understand it, it's not a simple task. Models are walk-through-able and the map maker must handle collision himself if its needed (such as for tree trunks). But of course, we could always use more vegetation models. We could also use mappers like Tilli who are taking the time to touch up the old RMAs.
Secondly, I note that the line work for roads is implemented as secondary texture layers, can those texture layers be the size of multiple tiles? Could I, for instance, make a pile of leaves or trash which sat as an extra texture layer over a 4x4 grid? I ask because I seem to spend a lot of time zoomed out in game, and at that angle the grass tiling is very noticable, if I created a series of large secondary texture layers to break up the monotany of tiling, how likely are they to be implemented? Too hard? Too unwieldy? The same kind of thing could be applied to large concreted areas, with a cracked or dirty overlay, would map makers use them if I made them?
The blending of one texture over another is done with
the material system. Currently, however, you can not mix and match texture dimensions of the "base" texture and the textures that are blended over the top. That means you can't have a 512x512 grass texture that has a 1024x1024 leaves texture blended over the top. Or at least, as I understand it, if you did that the leaves would be scaled down to tile every 512x512.
Two things to note, though. 1) Many of our old grass/ground textures are small (256x256) and not of great quality. You could probably reduce the tile by making newer, hi-res textures and changing the maps. 2) There is nothing to stop you from taking a 512x512 texture, making a 1024x1024 texture out of it (via tiling) and replacing the map texture with that to then use a 1024x1024 leaves blend. You always need to keep the balance between visuals and performance in mind, but most of our maps were made long before our engine was better optimized, and they can stand some higher-res textures.
And finally, how about terrain deformation? Can we do persistent burn marks and impact craters (texture only obviously)? It seems a bit strange how little lasting impact a volley of grenades seems to have, if its just a matter of making textures I could work on that too.
Actual terrain deformation is not possible without a substantial rewrite of the engine. I don't know what is possible in terms of texture overlays, whether it would be possible to put a burn mark around the area.
