BIM Coordinator Program (INT) April 22, 2024

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problem with alpha channel, need help?

Anonymous
Not applicable
I'm very new to ArchiCAD...I created an alpha channel texture in order to get joints on a wood floor, but when I rendered it (lightworks) w/ the bump map selected, there is a strange texture that shows up in what looks like a tile pattern (there are perfect portions of the floor adjacent to the textured portions...looks like the 'tile' pattern). Any ideas on how to fix this as it is obvious the floor would look a lot better w/ the joints?

Top: w/o bump map
Bottom: w/ bump map

7 REPLIES 7
Dwight
Newcomer
It also seems that there's some noise in the mask that adds roughness to the surface. Can you post an image of your mask?
Dwight Atkinson
Anonymous
Not applicable
I thought it might be the mask too, so I double checked it for noise. I think it is clean.

Dwight
Newcomer
displacment settings?
Dwight Atkinson
Anonymous
Not applicable
What are displacement settings and where are they? I'll test them to see if they can resolve the problem.

WHAT I FOUND OUT:
It only happens when a TEXTURE has an Alpha Channel w/ Bump Map selected and, only with Reflections & Specular are turned on. If either Reflection or Specular is off, the problem disappears. When turned on, reflection can not be set to higher than 25 or the speckle affect will return, but the floor looks dull.

WHAT I CHECKED: different lights, sun, background, map w/o alpha channel but w/ bump map selected, specular color variations, original PhotoShop texture in tif and pct. Tested some of the settings in Lightworks Effects (ultimately I set them on highest). The problem is only w/ the Lightworks rendering engine.

There are other settings in Lightworks Environment>Foreground which I do not understand. I tried the setting Foreground>None and the flaw still showed up.

Thanks for your help.
Dwight
Newcomer
Displacement is the LightWorks shader where you put your channel mask if it is not already in the iimage file.

This is complex because LightWorks actually bridges between the way the internal engine sees a texture and the way LightWorks does.

If the image has an alpha channel, then Lightworks uses it for specified shader effects. If not, it looks for an image file in a shader parameter list.

Mostly we uses "rough" to make surfaces have less glare, approximating paint applied by a roller..... or stucco or whatever.

See attached.
Dwight Atkinson
Anonymous
Not applicable
I checked out the displacement in Lightworks shader and couldn't get anything to work effectively but that might be because I don't know enough about what are the best settings.

Still, I don't understand why this should happen in the first place using Lightworks and the internal engine. I think this is a glitch in the program itself. If the program can create 3D textures using the alpha channel, then it should do so w/o artifacts showing up. Unless I'm using the wrong PhotoShop format for the original texture/alpha channel or something, it should work w/o any problems.
Anonymous
Not applicable
After learning a bit more about Lightworks, this is what I figured out w/ your help Dwight.

In Material Setting, select your material, Click on 1(Match w/ Internal Engine), then Displacement...change the Amplitude and Softness settings to lower settings above 0. While I can still see the texture in 'C', it is definitely usable. Now that I've got the basics working, just need to clean up the alpha channels and textures a bit.

Thanks.

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