Problems displacing sinusoidal-type cladding

[tricky]

I'm investigating using displacement to render sinusoidal cladding, but can't figure out how to create a smooth curve at the trough and the peak. The attached graphic should explain. The bitmap texture for the displacement was created in Photoshop using a gradient fill.


What am I doing wrong?

[joconnell]

Photoshop might be doing some gamma nonsense for it. You could try modelling the geo in max as a repeating patch, then render a floating point tif of a zdepth channel that covers it to get a nice pure source.

[rivoli]

I guess you just need a smoother/wider transition between black and white. as you can see from your screengrab, once applied to the plane, the gradient creates quite a narrow white line, which in turn, once displaced, form a peak instead of a curve.

edit:

You could try modelling the geo in max as a repeating patch, then render a floating point tif of a zdepth channel that covers it to get a nice pure source.

that's what I would do too, it's much easier to model a small portion of the geometry you'd like to get displaced, instead of trying to figure out the correct curve with gradients..

[ahosking]

If you know the gradient for it, why not use a gradient in 3ds max instead of a created image? That should sort things out for you too.

[tricky]

First thing I did was try the max gradient map. I think I figured that it was my blur was set to 0.001! If I crank it up to 0,5, the smooth curves start to appear.

I also considered modelling a small repeating pattern, but I couldn't work out how to create a zdepth properly. I guess I'd have to create a camera looking down and choose a zdepth start and distance value that accurately matches the geometry. I wasn't sure how the camera perspective would work though...

[joconnell]

Render from a front, top or side viewport and it'll behave. Or turn you camera to orthographic. I think dmitri did a little thing on it a while back for chain mail / linked fences?

[tricky]

Render from a front, top or side viewport and it'll behave. Or turn you camera to orthographic. I think dmitri did a little thing on it a while back for chain mail / linked fences?

Cheers mate!

[BBB3]

Orthographic camera is the answer.

I covered similar workflows on my blog and at Ronenbekerman a while back. Try here or here.

Peter did something too here.

[tricky]

Next problem. I am getting horrible triangular shading that conincides with the subdivide modifier I have applied to the perimeter line. The line is imported from Autocad, a subdivide modifier applied to that (set to 5000mm), UVW applied to that and then the VrayDisplaceMod on top. Any ideas?

This is one of the reasons we tend not to use displacement, but there must be a good way to solve it.

[flino2004]

Maybe is the gamma, set it 1.0 for that map

[tricky]

Images showing my problem.

[dlparisi]

If you can - 2D mapping in the disp modifier should clear that up.

[rivoli]

Next problem. I am getting horrible triangular shading that conincides with the subdivide modifier I have applied to the perimeter line.

subdivide won't work well with displacement. the modifier was meant as a help for radiosity, where you needed triangulated objects for better solutions, but vray displacement needs clean, all quads geometry to work best. imported geometry, if not cleaned up having displacement in mind, might not work at all.

[tricky]

subdivide won't work well with displacement. the modifier was meant as a help for radiosity, where you needed triangulated objects for better solutions, but vray displacement needs clean, all quads geometry to work best. imported geometry, if not cleaned up having displacement in mind, might not work at all.

OK. So I have a perimeter line. What would be the best way to get that into a displacement-friendly format?

[joconnell]

Also I'd imagine that Autocad doesn't do the best job of making geometry. The vray displace is like pretty much any other subdivision so it'll work best on a model that has evenly spaced, roughly square shaped quads. I could see autocad doing some pretty manky tesselation, similar to what'd happen if you convert a closed spline shape into a mesh or extrude it - it'll do a really shitty job with long thin triangles flying all over the place. Maybe look at quadrangulate or even horror of all horrors, do a re-model depending on what it is you're doing.