Itoo Software Forum

Forest Pack => Forest Pro (*) => Topic started by: Straightface Studios on February 22, 2016, 11:12:55 PM

Title: Feature Request: Vray Displacement Support
Post by: Straightface Studios on February 22, 2016, 11:12:55 PM
If you feed an Object's Vray Displacement Mod map into the Z-Offset in Forest Pack it will align a forest pack to the displaced terrain.   However if you do this, you can't use ZOffset, you can't use slope and you can't use height limiting.   You also have to calculate as a % of the height of a tree the displacement percent which is annoying when changing tree models.

It would be nice if you could have it look at the Vray Displacement mod and just assume that it's on the Z-Axis at least as well as generate a normal map internally for your slope calculations.     When I've got 16k displacement maps it isn't really feasible to tessellate out the displaced terrain for ForestPack to analyze.   And you're very close with the Z-Offset, you just need to add an additional Z-Offset with some basic math to scale it earlier in the order of operations.
Title: Re: Feature Request: Vray Displacement Support
Post by: iToo on February 23, 2016, 11:03:22 AM
I'm afraid this is a limitation which we cannot solve. V-Ray displacement is computed at render time, so Forest has not information of the final surface when items are scattered (which is done before render starts).

The only work around would be use a standard displacement modifier, but as you pointed out, this is not always possible because the size of the final mesh.
Title: Re: Feature Request: Vray Displacement Support
Post by: Paul Roberts on February 23, 2016, 04:03:28 PM
Hi!,

Using the effects feature found in the Forest Pack beta I've been able to use the map from the VRay Displacement Modifier to calculate the Z position of segments without the user having to do any tricky maths. This effect will automatically derive the size of the scattered objects and perform the calculations necessary to match a displaced surface. Also it's linked to  the modifier's Displacement Amount value, so the surface and the FP object will always be in sync. Unfortunately using this technique Surface > Limit By Altitude and Surface > Scale falloff commands don't work, so I've also added some additional basic controls for this purpose.

(http://docs.itoosoft.com/download/attachments/20480091/displacement.png?version=2&modificationDate=1456258303782&api=v2)

At the moment slope angle calculations still aren't possible but still this may still be helpful for some uses. You can read more about the effect and see how to set it up including a sample scene here: http://docs.itoosoft.com/display/FORESTPACK/Place+items+on+a+displaced+surface

I hope that helps, please let me know if you have any questions.

Many thanks!

Paul