Advice for a tree model

A.Kindu

Hello everyone,

I recently finished my first tree-model in 3DSMax. It is intended to be used for a game, and billboarding isn't possible. I had to keep the polycount below 3.4k.

I used the excellent 3d-motive tutorial to get started and this is the first result. Just to explain: I modeled the branches as high poly and then baked a diffuse and normal map from it.
I'm still a little unhappy about the positioning of the leaf groups, especially at the top. I think that it looks too sparse and the angles are too artifical, but I don't know what else to do in order to keep it looking dense and full from all angles.

Is there any advice you could give me? I'd sure appreciate every little bit I could get. :-)

(The total polycount is 3.400 at the moment)










And finally, a rendering:



Thanks in advance and all the best,

A. Kindu

Nosslak

I'm not amazing at making trees or anything but here's how I made the branches for one of my trees:

The trick is to make the branches non-planar, that way they'll look fuller from most angles. You should also bake some ambient occlusion to the vertex colors to amplify the depth and bend the vertex normals (not shown in my example, look it up on the wiki) to get better lighting.

My branches are kind of expensive (12 triangles, 24 when doublesided) but it makes the tree look fuller than just a regular plane. My tree consists of about 2k tris.

Also billboarded trees look horrible so I think you should try to stay away from those if at all possible.

DInusty

Very good post Nossiak,

One thing that really helped me was thinking about these things:

Whats the tree type?
what is the time of year and how does that tree respond to that time

Above all else is tree composition! How does it grow? Where are the more lush branches? where are the shorter dead leaves and branches? these are things that really help make the tree look right.

Some interesting rules I tend to stand by as well are things like every time a branch breaks away from its main branch its about 50% the diameter of the branch it came from.

hope that helps.

Nosslak

Oh, also I forgot to mention that if you place the branches as special/linked/whatever copies of each other (so that if you change one of them you change them all) the creation of LOD versions turns trivial. So doing this could then (in theory at least) easily negate the effect of the more expensive branches as they can be swapped with a lot cheaper versions without much visual loss at a distance. My example can be simplified down all the way to two planes (or even lower if you want to be extreme but then you'll get other problems).

A.Kindu

Hi,

Thanks for your replies! I tried the modifications you suggested, and though it looks a little better now, it still looks way too blocky ingame. I suppose it is due to the vertex normals. I tried bending them so they all point away from themselves, but it simply doesn't make a difference when I port the model into the game.

Is there any good step by step tutorial on bending vertex normals? I tried doing it with the speed tree script, and even though the normal now point in the right direction, it doesn't make a difference.

Thanks in advance for any help!

A.