Planetside Software Forums

General => Terragen Discussion => Topic started by: groverwa on January 06, 2007, 11:17:03 PM

Title: vertical erosion (weathering down the slope)
Post by: groverwa on January 06, 2007, 11:17:03 PM
Can someone exolain the following please.

How do i get weathering (erosion) down the slope of a hill or mesa as caused by rain rushing down the terrian?

Also is there a way to place different textures/ colours on individual hills etc in a scene?

Mike
Title: Re: vertical erosion (weathering down the slope)
Post by: Oshyan on January 07, 2007, 05:34:58 PM
There is a basic Erosion function which you can use on heightfield terrains. In the Terrain layout node list select your heightfield then click Add Operator at the bottom of the list and choose Heightfield Erode v3.01. Adjust parameters to taste and click Erode Now. This can give fairly good results, but other applications will probably offer you better control at this point (e.g. World Machine, Geocontrol, etc.).

To control texturing individually for specific areas of the terrain (specific hills, mountains, etc.) you would need to use some kind of masking function, either image-based or procedural. Depending on how you are doing your texturing this may be handled in different ways, either through the Fractal Breakup input of a Surface Layer or with the Blend Shader input of most other kinds of nodes. This thread gives some working instructions for using the Fractal Breakup input to mask a Surface Layer with an Image Map: http://forums.planetside.co.uk/index.php?topic=94.0 Once you have the basics of masking down, you would create an image mask in your image editor of choice that would constrain your texturing to the specific areas of your preference. You could use multiple image masks, one for each area/surface layer you want to mask.

There are some alternatives to this approach but I think this would be the most straightforward at this point. In the future we hope to implement a direct painting solution that would allow you to much more easily control this kind of masking from within TG2.

- Oshyan
Title: Re: vertical erosion (weathering down the slope)
Post by: groverwa on January 07, 2007, 09:28:05 PM
 Oshyan - thanks for the advice

the erosion will work with terrain but not with inverted crater shaders - any idea how to just erode the inverted craters please

mike

Title: Re: vertical erosion (weathering down the slope)
Post by: Oshyan on January 07, 2007, 09:31:07 PM
The crater shader is a procedural displacement effect which is incompatible with heightfield-based erosion. You could convert your crater to a heightfield using Heightfield From Shader and then erode it, but you may lose some quality by doing this.

- Oshyan
Title: Re: vertical erosion (weathering down the slope)
Post by: groverwa on January 07, 2007, 09:32:24 PM
thanks - mike