Grass Options for nXtRender

[Rich Hart]

A user asked about the different ways to add grass to a model. Below are sample renderings showing 3 different approaches, along with links to download the groundcover and material files used.

1. Textured Material - Use a material with a grass texture image.

This model was rendered by simply using the textured nXt material call Grass-Rye_Dark.ArMaterial.

This material is included with the standard nXt Material Libraries that can be downloaded here:

http://s3.amazonaws.com/mcneel/accurender/nXtMaterials_20110218.zip

2. nXt Groundcover - Use a nXt grass groundcover to represent the grass.

This is the same model with a grass ground cover applied to the lawn:

This creates a more realistic looking grass, since the groundcover add geometry representing blades of grass to the rendering, but takes more time to render than a simple textured material.

The nXt groundcover used for this rendering can be downloaded here:

http://www.renderplus.com/downloads/Other/nXt_Grass/nXtGrass_Ground...

You can experiemt with the settings for the grouncover file, to change the size, density and other parameters, by editing it with the nXtPlantEditor which is installed with nXtRender. Note: You can change the height of the grass by changing the Foliage Width. Because the aspect ratio of the blade of grass image is maintained, this will also set the height of the blade.

Note: The groundcover file (*.ArGroundcover) can be selected and added to the model from this menu:

3. Displacement Material - Use a material with a displacement texure to add nodes of height to the image to simulate blades of grass:

The nXt displacement material used for this rendering can be downloaded here:

https://www.renderplus.com/downloads/Other/nXt_Grass/Grass- Displac...

 

Use the nXtMaterialEditor to change the Height, Facet, and Z Offset for the displacement.

1. Height is the height of the displacement (from the surface) ie longer blades of grass.
2. Facet is how the surface is broken up. Higher will have more detail. Like facets of a curve.
3. z offset is where the surface plane starts. You may want to push the surface back to accommodate the lift from the height variable.  

To help you get started using these different types of grass, the model used for these sample renderings can be downloaded here:

https://www.renderplus.com/downloads/Other/nXt_Grass/3D House.dwg