mapping advise for plant objects?

Bronco

hey guys

I understand this answer may change depending on engines etc but I am lookign for a general rule...if there is such a thing and general way of thinking when doing such things.

Basically I have me a plant,its in a pot,has a stork,then of course the branched/leaves as planes.

My question is How should I go about mapping this?
Should I cram it all onto 1 texture map and use alphas where nessary,or should i do the leaves on a small dedicated texture with alpha applied and the pot on a seperate texture map (I have found however this wastes alot of texture space on the map and I can't see a way around it)

Thanks for any advise.

John

MoP

Personally I would map them all onto one texture sheet. For the alpha'd leaves, just re-use as much texture space as possible (without making it too obvious), so put the uv's for a set of leaves on one side of the plant, right on top of the uv's for a set of leaves for the other side (except maybe flip the UV's upside down or something so it's less obvious that it's the same texture used again).

I think doing it on 2 different textures would only really become an issue on console games since they usually have limited texture budgets, so you wouldn't want to use alpha on a large texture if only a small part of it actually "needed" it.

That's what I think anyway.

Eric Chadwick

I usually do the non-transparent bits in one shader, and the alpha'd bits in another. That makes sure the pot and branches don't incurr an alpha pass, and lets me turn off backfaces only for the alpha.

But if I model in the backfaces, and I'm only using alpha-test (1-color hard-edged alpha), then I find it's better to stick everything into one texture.

malcolm

This is a great question. If you are building for a game the easiest way would be to ask your render programmer what is the cheapest. As you mentioned it really depends on the game. On our game if we had a model containing only one mesh it would be cheaper to have only one texture for the whole object as extra materials cause extra data which can get expensive when you have thousands of instances in your environment. For our tree models we actually make them with 2 meshes in a hierarchy this is for audio tagging actually, so since we already have two meshes it is no extra cost to have one texture for the trunk and one texture for the leaves. Some engines don't support self sorting as well so you may have to break it out into two objects and two textures just to get it to work correctly in game. As a rule of thumb I would try to keep it to one texture if you can.

Bronco

thanks for the replies guys.

Malcolm this plant was for my demo reel,before I canned that until my drawing/sketching improves....so its acturally now just a general modelling/exsperience gaining exercise.

Hopefully ill get round to putting a BIG update on my site,which will include these attempts at organic matter...hehe.

Cheers

john