Cliff/Rock Placement (based on ground geo)

[Nintenjo]

Hi, Im looking to use FP to try and scatter rocks at the base of a cliff face (see image) I want the rocks to gather on the geo against the clifs based on some rules but im struggling to see what rules i can apply in FP to achieve this kind of look. Ideally we want larger rocks at the back (closest the cliff) and smaller rocks further from it (which i could do using some distance falloff.

However what i want to avoid it having to scatter all of these by hand via painting, we have 1000s of cliff faces so need a way to generate the placement, maybe based on a mask i render to texture i thought maybe with some noise added for variation Trouble is do masks in FP has falloff rules as they cant determine the edges?  Ideas welcomed..  I also dont have the luxury of using altitude control as all our cliffs are at different heights.

[Michal Karmazín]

Hi,

For these purposes, you can use the Altitude Range and Slope Angle Range features under the Surfaces rollout. I hope this helps!

Best regards,

[Nintenjo]

@Michal .. unfortunately i cant use altitude as in my message above i stated all our cliffs are at different heights (see image)..  Slope angle is also not really that useful as in out case the cliffs are near vertical vs the ground which is flat. (See image) of our cliffs model with a paint over as to how id like to scatter my rocks FP assets?

[RealViz]

For this purpose I would choose UV paint. As in the tutorial:
https://www.youtube.com/watch?v=A7s2sE0ELKg

[Nintenjo]

Thanks RealViz that was useful although it will still require me to paint the areas that are the base of the cliff, i might see if i can AO to render those areas.

But an issue i have when testing this method is even though i am painting in the Canvas using UV Channel 2 the distribution map is using UV channel 1? Ive i paint into UV1 it works fine, but i need my existing overlapping UV1 channel untouched, so want to make a new one for my distribution. But the option to change it is Greyed out in the UV?

[Tobias Jansson]

Now this might be o long shot but I think I did something like this some time ago using the Pits & Peaks script over at scriptspot.com. If I remember correctly it works on vertex colors and might save you from having to do a lot of painting.
/Tobias

[RealViz]

I also thought of using the DataChanel mod. This would make everything more automated again.