A is a geometry replacement system. Instead of loading the full, high-poly mesh into the viewport memory, V-Ray creates a lightweight "placeholder" object. This placeholder looks like a low-poly box or a simplified mesh while you work.
Trees are notoriously complex. A single realistic oak might have 500,000 polygons. If you want a small grove of 50 trees, your scene is suddenly pushing 25 million polygons. By converting these to proxies, you can scatter thousands of instances across a landscape with almost zero impact on viewport performance. How to Find Free Downloads vray proxy trees 3ds max free download
Most people scroll past this, but is now included with your V-Ray installation. They have a growing library of free trees and plants. A is a geometry replacement system
Your trees will look floating without proper ground. Use V-Ray Displacement on a plane with grass textures, then instance small bush proxies or grass patches around the tree bases. Trees are notoriously complex