Been having a ball tonight playing with a new idea I have had. It worked so well I just had to share it. Working on the community mapping I have some towns and were gonna need a lot of buildings and there is no way I am going to draw each and every one of them. So a long time ago I figured that I could make bits of building and use them as stamps in ViewingDale or any other kind of stamp based drawing package like DungeonForge I guess. Did that pretty successfully with tiled houses but when I tried thatching it was a lot harder because thatched houses have a lot of curved surfaces and whilst tiled roofs have defined gutters, thatch does not. Basically it didn't work and I gave up.
That was a while ago and things have moved on. This tutorial is going to use some pretty advanced techniques in 3D and I don't know what package you might use for this and its going to be tough going unless you can automate the process too. But its the only way I have managed to get good results so far. Apologies in that I am not going to intimately describe key by key steps as all of the software I am using will be custom but the idea should apply to any 3D package that can do lighting with a paint package that can do alpha masking - gimp, PS, PSP etc all can for example.
So how to create fast thatch for curved surfaces.
The object to be thatched needs to be in 3D so as stated that this is for dummies here is one
What you need to do now is get that object in your 3D app. This could be a house object of course so making that might be a bit easier. The point here is to show that its good for curved surfaces.
You now need to set up two lights opposite the object, north and south and render it to give the first light image. Then you need to set it up so that the lights move around the object in steps. I am using 8 steps so that it goes :- 0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5 and 180 is the same as 0 so no need. You need one more which is lit from above too. You can do that as an 9 frame scene and render all of the frames out in the scene at once.
Right you have 9 mask renders. You need to get some thatch and I got mine from a composite of several at CGTextures.com as usual.
Make one with thatch going north south. Then make another with a 22.5 rotation, then another at 45 etc all the way to 157.5
For the top down mask I used several of the rotated thatches blended together to give a no-particular-direction thatch.
Now multiply all of the thatches by the masks and add them up. You should get something like that of the final render.
I have this scripted now so for any height map I can generate them thatched in no time. It could in theory do more than one house at the same time - maybe a whole village... The nice bit tho is that you now are freed from having to texture each part of every 3D object saving hours if not days of time.
Hope that is useful to somebody daring enough to try. I will of course be adapting this for all sorts of roof materials so I am on the hunt for non-copyrighted 3D houses now. If you wanna build them then I can thatch them for you.