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fade off for noise displacement applied to regions of a surface


willtris

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Hi there,

I am using noise to displace geometry that I can export for 3d printing. The goal is to limit the displacement to an arbitrary region (or regions) of the surface, and to smooth the transitions at the borders of the regions so that the intensity of the displacement fades to zero across some definable distance.

For the moment, my displacement region is simply set by lasso-selecting contiguous polys as a Group referenced in the Pointvop, but I would like to be able to work with regions defined by intersections with objects scattered across a surface.

Any thoughts on approaches I should try would be great - as I am pretty new to Houdini, I will definitely appreciate as much detail as possible.

Thanks in advance! 

 

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Hi 3dome,

That's interesting - thanks for the example. It's my first pass at working with the Atttributeblur.

I rejigged it to work with the normals so it suits the geom I need. As you say, it's a little difficult to set the width of the transition zone. Also, I'm not sure if there is a way to restrict the blur so it extends only to one side of the boundary.

I was wondering if there is a way to use the intersect seam from booleans to define the boundary of a surface region (or just to use the subtracted surface piece) and then to offset an arbitrary distance into the interior of the region - perhaps using a down-scaled copy of the cutting object - so as to define the transition zone. The bit I'm not clear about in this case is how the noise effect is ramped across the transition.

Another route I wondered about is whether, using an Attributetransfer between objects, it's possible to control the range and the profile of the fall-off values so they transition from zero to max and then plateau across the central area of the noise region.

Any thoughts much appreciated!

 

 

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so this new version has a customizable falloff ramp and sorta uses the seams of a boolean. I have no idea if it's possible to really define arbitrary shapes as boundaries.. I'm sure there is a way but I just have no idea ;)

regarding your last question: on attribtransfer you could set the blend with (that would be your range) and feed that into a spline ramp to remap the values to your liking

Cheers

dm_regionDisplace_v02.hip

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