image map as a mask but limited with Altitude constraints - How?

[fferro]

Hi,
I need to populate some instances over a heighfield, controlling the spread by a mask.
I've created an image map shader with a standard B&W tiff file.
How could I limit the altitude of the population?

Blend Shader? Surface shader? Which one?
Thanks

[Saurav]

Connect the image map to a surface layer with these settings:

Coverage: .5
Fractal breakup: 1

You can restrict the altitude via the surface layer settings. You also need to have the image map correctly projected on to the terrain with the right scale settings.

[fferro]

Hi Saurav, thank you for your answer.

"Connect" means the output of the image map to the input of the surface layer?
Why .5? This will get a 50% of the image map passing through the Surface?
thanks again
Fernando

[bobbystahr]

I think the second number should have been 2 not 1 if you are still having trouble getting this to work....it's what I use in any case and have flawless performance

[FrankB]

Why .5?

Anything more than 0.5 will add additional coverage to what the fractal breakup allows for.
It's almost like fractal breakup = 1 means that the influence of the breakup shader is at it's maximum. However, the surface layer shader will increase the coverage beyond what the breakup shader determines, if the coverage level is higher than 0.5

It's not that I have the correct explanations as to why this is so for you, but I know that practically it works like that.

[Saurav]

Sorry I should of added connect the output of image map to the input (breakup shader) of the surface layer.

Check this thread for detailed answer.

http://forums.planetside.co.uk/index.php?topic=864.msg8415#msg8415