lot of tree
 

hello
I have to build a scene in a forest
but with all the trees the scene is very heavy and it crash my PC
even if the trees are in a non visible layer
can i use a " dummy " which will be a simple polygon who will launch a model in render ?
PS : excuse me for poor english!!

Well, one thing you could do is model a tree, duplicate it several times, place them where you want, then hide each copy. Once you are done modeling the rest of your scene, simply unhide them and render it out. Once you unhide them, however, you should not move your camera around at all. Get your camera where you want the render to be taken, then unhide them. This should prevent your system from crashing. Another way you might be able to do it is to create a few trees, take a picture of the trees (either render it out, then save as jpeg or Alt+Print Screen and paste it onto microsoft paint), then place that image onto a plane. You can then place this behind your scene and follow this proceedure to illiminate the black background you will have.

http://www.rhonda.com/Maya_TopTen_02.html

Hopefully you understood all that.

I suppose you could use some low poly proxy objects for the trees and then use a pre-render MEL script to replace them with the real tree models at render time. When the render is over you could use a post-render MEL script to revert to the proxies. Of course this is a bit involved and troublesome but it works...

In addition you could put each tree in it's own render layer (not display layer) and render in passes using image format that supports alpha channels (such as maya iff, tif or tga) and then composite the resulting images in photoshop or some real compositing package like after effects...

thx for those replys
kbrown do you know where i can found a tutorial about low poly proxy objects

The easiest way to have a low-res proxy is to just make something like maybe a cone and stick one where every tree is, then hide the original. This will at least let you work faster when you're not rendering.

As for making renders work, one way (usually the best way) is to divide the trees into layers and render each layer separately, then composite. Another way is to use lower-res trees for those that are in the distance, or even replace faraway trees with a 2D image mapped onto a plane. If you're careful, you'll never be able to tell the difference and it will render much faster!!

-- Mark