So far i've downloaded several sample of low polycount vegis (3ds format) and they've crashed my Carrara 5pro. the internal plant maker is too heavy for my needs (got a city to vegetate)....any suggestions?

Do you have a wireframe image of the plant that you can post here to see where the problem may be in the model?

Try the free app "Plant Studio".

Attached Link: http://www.loopix-project.com/models/con_plants.htm

where it says free sample www.loopix-project.com/models/con_plants.htm as a standalone within carrara it worked...placed in my city, it crashed. I replaced the .tga with a .png, but that didnt help

http://toucan.web.infoseek.co.jp/3DCG/3ds/FlowerModelsE.html And try this for more trouble free FREE stuff.

I downloaded the freebee tree from loopix and installed into th Carrara browser via the 3ds version. I clicked the image file in the shader dropdown as save internally though just to play safe. Used in a couple of Carrara scenes with no problem.

The OBJ import didn't map very well out of the box for me. The 3DS version looked a little better when rendered. Free models always need re-editing to make them work. That's why they're free. The lo-poly 3DS tree rendered here took awhile because it uses over-lapping transparency planes (that light goes through) with tree images applied to them. Carrara trees render much quicker and look much better. But they are hi-poly. Which makes me think that your scene is crashing Carrara, not the free lo-poly tree.