Flat mapped Grass Options?

[MegaPixel]

I've checked the other forum posts on Grass allready which are a few years old by now. I was wondering if anyone has come up with any relativly modern tricks for getting the most out of your flat mapped grass? I'm working on a huge exterior community animation with RPC's and such and I'd like to find a grass solution that lives up to the quality of everything else but using the default archmat grass's that come with MAX don't seem to cut it or maybe I'm not using them correctly. I don't realy care for the 3D options because of scene optimization but I'd be more then willing to pay for a professional grass library if that's what it takes. Any thoughts?

 

-Mega

[Chad Warner]

I think the best solutions come from using several different grass images mixed together with a noise mask (or smoke, or whatever) to help with the randomness and tiling problems.

[Jennifer]

Hi,

 

Agreed. You can use a Mix map style between two different grass bitmaps, and either set the mix amount to a value, or use a map such as Noise to do the mixing. In Noise, set the Size value to what looks best in your renderings. In the map settings for one of the Grass maps, Rotate in the W axis to 30 or 45 degrees, and also change the tiling and offset values. This way, with one UVW Modifier on your grass objects, you can get different mapping for each bitmap.

 

A Composite material will give you more options, but generally we use a Mix map in a standard material.

 

Also, avoid flat grass planes as much as possible. Use the Bevel modifier on a closed Spline defining your grassy areas, and give it some height and a negative outline amount. Depending on your shape, you may have to start with small increments and see how far the shape will go before you lose capping. The Bevel modifier has the potential to send 3ds max into never-never land with complex shapes, so it is a good idea to use the modifier on a small grassy area first to get the settings right before using it on a lager or more complex shape. Always save often, especially before adding this modifier!

 

For best results, use a couple smaller Levels in the Bevel, and use the Smooth Across Levels option to eliminate the hard-edge that can be created. Use Curved Sides if you’ll see a segmented side. A Smooth modifier with Auto Smooth set to On helps, too.

 

If you have grassy areas with trees, shrubs and flowers, create shapes that define areas with mulch around the trees and under the plantings, then create a Shape Merge object out of your grass object and use that mulch-area shape to add detail. The Shape Merge object has an option “Output Sub-Mesh Selection”. If you set that to Face it will send the faces in your mulch areas up the stack, and then you can use an Edit Mesh or Edit Poly to do more editing on those areas to give depth, and also to change the Material ID numbers for those faces to a new number for a Grass/Mulch Multi-Sub Object material. 3ds max will automatically create a MSO material if you drag a new material, such as cypress mulch, on to selected faces.

 

The shapes you merge should not go over the edge of the grass object for the Output Sub-Mesh Selection to work best, I have found. Worst case is you’ll have to manually select the faces you want to modify.

 

Have fun!

[MegaPixel]

Jennifer,

 

Thanks for taking the time to give that detailed response. Your technique sounds good and I think I'll go with it. You rock - Mega