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How can I get the Bump property to work?

lukon100lukon100 Posts: 761
in Technical Help (nuts n bolts)

So far, my attempts to use the Bump property in texturing have failed. I put a bump image map in and dail the values to their maximum, and I see no effect whatever.

So it must be that I have no idea how to use the Bump property.

Can someone please explain it?

Comments

  • GordigGordig Posts: 9,163

    What render engine are you using, and what object(s) are you trying to apply bump to?

  • lukon100lukon100 Posts: 761

    Gordig said:

    What render engine are you using, and what object(s) are you trying to apply bump to?

    Iray.

    The object is some poser clothing made for V4.2, to which I have applied an Iray converter. The Iray converter has created the Bump property.

  • GordigGordig Posts: 9,163

    Can you remove every map except for bump and render it?

  • lukon100lukon100 Posts: 761

    Gordig said:

    Can you remove every map except for bump and render it?

    Thanks for the diagnostic trick. That worked. It revealed that the Bump property does have some effect. But the effect is very small, such that it would not be noticable with the other maps applied. Removing the property limits and cranking it up to 4000 does not help. 4000 is no different than 10.

    So, I'm gathering that the Bump property is simply not designed to produce surface deviations of the magnitude I would notice in this situation. I want to produce surface deviations of about 3/8ths of an inch.

    What property can produce surface deviations that big?

    Is the Displacement property the only property that can do that?

    If so, my next problem is that the Displacement property, while producing big surface deviations, also produces some gaps in the UV seams of the garmant.

    And my corresponding next question would be "How can I get rid of those gaps?"

  • GordigGordig Posts: 9,163

    Bump doesn't affect geometry at all; it simply creates the appearance of geometry changes. It sounds like what you want is displacement, and it's important to know that displacement in Iray is heavily dependent on mesh density. What kind of gaps are you talking about? Can you post a render with just displacement applied?

  • lukon100lukon100 Posts: 761

    Gordig said:

    Bump doesn't affect geometry at all; it simply creates the appearance of geometry changes. It sounds like what you want is displacement, and it's important to know that displacement in Iray is heavily dependent on mesh density. What kind of gaps are you talking about? Can you post a render with just displacement applied?

    Ya here is a screenshot with just the displacement:

     

    Displacement Gaps 2.jpg
    1280 x 1024 - 826K
  • lukon100lukon100 Posts: 761

    Gordig said:

    ... displacement in Iray is heavily dependent on mesh density

    Based on this hint from you, I experimented with increasing the mesh density. I added a smoothing modifier and I converted the item to sub-d. This reduced the gaps drastically. I don't know whether adding the smoothing modifier had anything to do with it, because I did that at the same time I converted to sub-d.

    Although much reduced, the gaps are still present. And I'm pondering how they could be completely closed. I imagine I would have to make actual UV maps for the textures, instead of just tiled texture squares. Then I could make a displacement UV map that faded to black at these seams, thus correspondingly fading the displacement to zero at the seams.

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