A bug in displacement textures?

Hi,
I am working in a simple test with displacement textures and I think I have found a bug. I need someone that repeats the bug. (Versions 2.44 and 2.42 fails)
The test:
Create a plane
Subdivide until around 66000 verts in my test (high density)
Set a new material with a wood texture. The texture has 0-0.499 black and 0.501-1 white color. Press only the displacement button
Render

I have added other texture with color to see better the render and the result is the first photo.
Then, I have eliminated this texture from the material and created a displacement modifier with the texture and the result is the second one.
The correct render is the second but I do not know why the displacement texture have failed.
I need your help to resolve if this is a bug.

Attachments



Keep in mind, that even though you are not mapping to the Nor, the Nor slider as well as the Disp slider also influences the displacement. I cannot explain in any detail how or why, I only know that it does.

Thanks OBI_Ron, but…
The problem is not the Nor slide. I have found it and I need a developer to know if it is a bug or a feature.
The problem starts when use a texture in displacement mode and a colorband. If you put the colorband with one color with Alpha = 0 everything works. However, if you put the two colors with Alpha = 1 (both visible) you obatain a flat displacement.
It is difficult to say if it is a bug.

it works ok for me…a little goes a long way, you know. I think the disp var is in Blender units. so it might be just Maxxing out right away.

Not a bug in displacement, per se. Texture Displacement works using the intensity values of your texture. When you give a procedural texture a colorband, the intensity values are changed to equal the alpha values (which is why, when setting one of the colors to 0 alpha, it worked). The Displacement Modifier works with the RGB values of the given texture.

If you want to use the Texture Displacement option, make sure to turn the “NO RGB” button on, located above the color options, next to the “Neg” and “Stencil” buttons. And, to make sure the displacement isn’t skewed, make sure to turn the “Nor” value all the way down.

Thanks, the key is the “NO RGB” button, now, it works!

This is almost never the case. Those guys pop in from time to time but they mostly spend their time doing what they do best cuz this end is fairly well covered.

I said developer, but someone documenting or a beta tester is enough.
Nevertheless, a skill user is perfect :smiley:
Thanks everybody

Hi Lads
I am having difficulty with displacement in Blender. I have a tile type bump texture and am trying to displace a simple cube with it. I want the displacement to be uniform with the tile bump texture. I am coming a cropper. The tile is here:

http://www.filterforge.com/filters/243.html

End of page for maps. Do you have to subdivide the mesh substantially to achieve proper disp? Which is best - Displace Modifier OR Disp button in the Map To tab? Does the above texture actually need to absolute black and white? A 1 to … step by step would be appreciated just to see if I am doing things right.

Cheers
Aidan

And a bonnie good day to ya, Aiden! a texture mapped to displacement physically moves the closest vertex. The denser the mesh, the more accurate the displacement. When mapping to displacement, a BW image is needed. Absolute (high dynamic range) is best, because you have a Disp slider to control the degree of the effect. for step by step, see http://wiki.blender.org/index.php/Manual/Displacement_Maps

Hi PapaSmurf,

I refer you to this other thread I started with a sort of a challenge:

http://blenderartists.org/forum/showthread.php?t=97826

The image you see there was done with Realsoft 3D [ www.realsoft.com ]. A 5x5 Sub Div surface only using Height type maps. I was wondering if this was possible in Blender with a low poly mesh such as this?This image used the same Bump Map from the site listed in my first message here
Cheers
Aidan

i saw that thread, and a 5-level subdivided mesh should be more than sufficient.2^5 is like a 1024 faces. have you actually tried it, and what is your result? post some pics!

Also - is their any particular file type that is best for bump textures in Blender - jpg, gif, tif. tga? Or does it matter?

Aidan

Hi PapaSmurf,

http://www.tidalsound.com/3dstuff/normal/disp1.jpg

I should say that I am a relative newb to Blender but not to 3D. Any ways this is what I end up with,

Cheers
Aidan

Lads,

The above image is using the bump from the Filterforge site I linked to in my 1st message here. Note the displacement is happening as undulations as oposed to following uniformly with the outlines of the individual tiles in the image. I used subsurf render level 3 here with a 5x5 subdiv

Aidan

Hi,

Ver 2.44 of Blender by the way …

  1. Added a bump texture as texture type image
  2. F5 - over to Map to tab - Enabled the Disp button as well as the Col button, set nor slider to 0, Disp slider to 0.158
  3. render
    Is their any changes required in The texture OR the Map input tab?
    I tried it by adding SubSurf Modifier set to level 3 Render also.
    Aidan

PNG and TIF and TGA (in that order) are good because they are lossless and you edit them often. gif is not supported. jpg is lossy and the image will degrade every time you save it, which destroys your quality and hard work.

Displacement Modifier:
http://i105.photobucket.com/albums/m233/KaiJoshu/Tile.jpg

Detail w/ wire:
http://i105.photobucket.com/albums/m233/KaiJoshu/TileWireEx.jpg

Plane Specs:

Dim: 20 x 20 (BU)
Faces: 64 (8 x 8)
Sub-Surf Level: 6
Faces After SS: 262,144

This image was done using the Displacement Modifier. All textures UV Mapped (To keep them consistent). Although I got similar results using Texture Displacement, It rendered with artifacts:

Texture Displacement:
http://i105.photobucket.com/albums/m233/KaiJoshu/TileTex.jpg

So, I would suggest using the modifier in this case, although results may be different elsewhere.

Hi Iokua83,

Thanks for the renders and tips etc. I have a few renders here:

http://www.tidalsound.com/3dstuff/normal/dispyaf1.jpg

This is done in Yafray using the Displace Modifier set to one Strength.

http://www.tidalsound.com/3dstuff/normal/dispyaf2.jpg

Another at a greater strength.

I think my original problem may have been a mesh that was too small. I tried with the plane size you used and all is well for the moment.

Cheers
Aidan

excellent. i was having crap results as well and said “self, just be patient, i am sure someone else can figure it out”. My mesh was too low-resolution as well. sweeeeet. Thanks iokua! You get the cookie today!