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Im trying to use a wireframe node to influence the height of a bump node, but it dosn't seem to have any effect: Wireframe Bump

As you can see in the second image, the wireframe node is behaving properly because it influences the diffuse colour perfectly: Wireframe Diffuse

Any solutions to this problem?

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There appears to be an issue with that node in conjunction with the Bump node. One solution that appears to work is using the Wireframe node in conjunction with a Normal Map node:

enter image description here

These nodes render a result like this:

enter image description here

Notice that these values can be inverted as well:

enter image description here

One word of warning thanks to @WChagrin:

I would say that that's almost certainly undefined behavior. The colored pixels in the normal map are supposed to represent unit vectors in tangent space. When the wireframe node outputs a value of 0, that's coerced into the vector <0, 0, 0>, which is not only non-unit, but non-normalizable. That is, trying to normalize it would require division by zero. Relying on this behavior is probably a Bad Idea™.

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    $\begingroup$ Seems to though . . . you can also influence the Strength value with similar results. $\endgroup$
    – J Sargent
    Jan 27, 2015 at 16:04
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    $\begingroup$ @GiantCowFilms Meaning you are using Cycles? $\endgroup$
    – J Sargent
    Jan 27, 2015 at 16:16
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    $\begingroup$ It does appear to be bug because I have baked the output from the wireframe node and it works perfectly. I can't recreate your yellow normal map (???), but I can confirm that the brick texture works fine, when the wireframe dosn't. I will go and log this on the bug tracker, Thanks for all your help guys. $\endgroup$
    – Christy James
    Jan 27, 2015 at 16:23
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    $\begingroup$ @NoviceInDisguise I made a workaround by baking the output of the wireframe node to an image file, and then using that image file to influence the height of the bump node, and that works fine for me. It would be interesting to find out why the wireframe node dosnt talk to the bump node though.... :) $\endgroup$
    – Christy James
    Jan 27, 2015 at 16:52
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    $\begingroup$ I would say that that's almost certainly undefined behavior. The colored pixels in the normal map are supposed to represent unit vectors in tangent space. When the wireframe node outputs a value of 0, that's coerced into the vector <0, 0, 0>, which is not only non-unit, but non-normalizable. That is, trying to normalize it would require division by zero. Relying on this behavior is probably a Bad Idea™. $\endgroup$
    – wchargin
    Jan 27, 2015 at 17:49
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This problem appears to be caused by the Wireframe node not talking to the Bump node properly. After a bit of disscussion and help from others in the comments I developed this workaround by baking the wireframe output to a file and using the file to influence the Bump node:

enter image description here

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  • $\begingroup$ Go ahead and accept your answer, it helps site stats $\endgroup$
    – J Sargent
    Apr 14, 2015 at 18:43
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Why you can't see anything:

The reason (or at least one of) is due to a limitation of normal mapping. All that normal mapping can do is trick cycles into think the face is at a different angle. In your case, if you look at what you're trying to create from the top, all the faces are the same angle. In order for this to work, you need a bit of a slope.

Using displacement would work well, except in order to have enough geometry to displace, you will mess up the wire frame :/

The reason why the normal map node works, is that it supports some very unconventional normal maps. The bump map node is more particular about its output.

As far as Ray Mairlot's comment, a brick texture won't work form the bump map node either, I have tested it to check, there is only a slight edge visible along the slope that occurs between the bricks.

The bump and normal nodes are different:

The Normal Map node takes a color representation of a normal vector and turns it into a vector.

The bump nodes samples 2 areas on the height map and compares the angle the find the vector. since there is only black and white, it will only find 90 degree angles and therefore not show any edge.

Paraphrased From the wiki

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  • $\begingroup$ Doesn't work on a sphere, I have a solution (I think) $\endgroup$
    – J Sargent
    Jan 27, 2015 at 15:57
  • $\begingroup$ @NoviceInDisguise Yes, it wouldn't, still no angle. the height map being converted needs to have a gradient in order to have an angle to give the illusion of height. $\endgroup$
    – GiantCowFilms
    Jan 27, 2015 at 15:58
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    $\begingroup$ Then why can a black and white brick texture create a bump effect? $\endgroup$
    – Ray Mairlot
    Jan 27, 2015 at 16:01
  • $\begingroup$ I tried mixing RGB values with the Wireframe node, and then putting that into the Bump node, and that didn't work either. $\endgroup$
    – J Sargent
    Jan 27, 2015 at 16:03
  • $\begingroup$ I think the bump node is a bit fussier.... $\endgroup$
    – GiantCowFilms
    Jan 27, 2015 at 16:07

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