Hurray Trees!

knak47

I know a question like this is always dependent on what system is running the game, what the art director wants, and many other factors. Well here it is...

I am going to make some trees for an outdoor environment. I have been taught how to make low poly ones, the kind where you model a trunk and limbs, well at least the limbs and branches that are at player height, then use polys with branch and leaf textures on them as youget higher on the tree. I also I really like the Tut in the wiki by Andy Zibits found here http://www.andyzibits.com/tut_particle_tree_generation.html

I am just wondering if anybody actually models out leaves and all the branches? Because in UDK the foliage map has trees where the leaves are all modeled out. Also I have seen people make trees where each leave is its own leaf card.

Thanks guys!

Ben Apuna

You should check out the Tree making fast technique? thread, and the Foliage section of the wiki though it sounds like you saw it already.

Each leaf having it's own leaf card sounds like a bad idea, but with the advances in GPUs and rendering algorithms who knows what will be possible in the near future.

It all really depends on so many factors...

One big thing to watch out for is the massive amount of overdraw foliage can create when using alpha planes. You can shape your foliage planes to closely match the non-transparent parts of the texture to reduce overdraw.

knak47

Thanks Ben, yeah I have read up on transparency techniques and know that Alpha Test is prefered over Alpha Blend when dealing with lots of transparent objects. And I will definitely be triming away the excess transparent areas from my cards.

I am just confused why Unreal would have all their trees have the leaves modeled out. Is there anywhere in the industry where that approach is used?

Or are their trees just to heavy compared to general techniques? And if the trees that UDK has in their foliageMap.udk level are to high poly, than what is a good ballpark for a tree that would run on a console, 1000-2000?

Eric Chadwick

Our MMO foliage artists use the technique where you model out a branch with all the leaves in high res, then render it out in passes (diffuse, spec, normal) for alpha-test planes. Works really well, but like anything else the artist has to be good at what they do to pull it off.

Tri count is totally variable, on consoles just like any other platform. How many trees will be in view at once, how close do you get to them, etc. In the 2000 range would be good for a portfolio piece tho.

knak47

OK, thanks Eric that's what I was looking for.