Comprehensive Detail: Physical Surface for P11


  • Poser Ambassadors

    I was working on a tutorial for you regarding rust on metal but now I'm distracted by an apparent bug in the shape of the 3d procedural textures. I see artifacts in your renders, too with my test pawn. What the hack is going on?

    Meanwhile, a sneak peek.

    alt text



  • @bagginsbill said in Comprehensive Detail: Physical Surface for P11:

    I was working on a tutorial for you regarding rust on metal but now I'm distracted by an apparent bug in the shape of the 3d procedural textures. I see artifacts in your renders, too with my test pawn. What the hack is going on?

    Meanwhile, a sneak peek.

    What kind of artifacts?


  • Poser Ambassadors

    For myself ... I did notice a stretch in the curve of the pawn's shoulder and again at the base. like texture striations.


  • Poser Ambassadors

    @Boni said in Comprehensive Detail: Physical Surface for P11:

    For myself ... I did notice a stretch in the curve of the pawn's shoulder and again at the base. like texture striations.

    Exactly. Look at my sneak peek. Look closely at the all-silver and the all-rust. Both exhibit weirdness on the shoulder and base. I see similar stretching along the square edges/corners. Pretty much wherever the curvature is rapidly changing, something is wrong.


  • Poser Ambassadors

    I thought that was user error. I thought I had applied the texture incorrectly. I used global coordinates and that helped a little, but it is still there as well as the "unlit" side showing a lot more shiny than it should as well as smooth.


  • Poser Ambassadors

    Wow this is getting more and more mysterious. I went back to Poser Pro 2014 and rendered with various procedural 3d texture nodes and everything looked fine.

    In Poser 11 I tracked my current artifact to a Spots node, so I made a shader with JUST a spots node for diffuse color in both PP2014 and PP11 and the PP11 one looked wrong. So then I saved the PP2014 prop to my library and loaded it into PP11 next to the one I made in PP11. They rendered differently!

    Then I copied the shader (select nodes, copy, switch materials, paste) from the PP2014 prop to the PP11 prop. Even though they were constructed identically. They still rendered differently! They also render differently in FireFly, so it's something to do with P11, not with SuperFly.

    Here's a PP11 Superfly render of the spots shader on two pawns. The left pawn was saved by PP2014. The right pawn was saved by PP11.

    alt text

    Again - I copied the shader from left pawn to 2nd pawn. There is no visible difference in the shader. So I'm thinking it's either a geometry bug or a deeply unobvious shader bug.


  • Poser Ambassadors

    The in-memory prop seems to be corrupted somehow.

    When I load new pawns from library, they do not show artifacts. When I copy those they do not show artifacts.
    When I clone one of these "corrupted" pawns, the copy also shows the artifacts.


  • Poser Ambassadors

    If I save a corrupted pawn to the library, and then load that, it is still corrupted.


  • Poser Ambassadors

    So - I do not know how this problem was created, but I now know how to fix it.

    You have to just abandon the prop - it is corrupted.

    I found that the shader is not corrupted. So here's how I fixed it.

    For each corrupted pawn:

    • Save it's material to a temporary file in your library
    • Delete the corrupted pawn prop
    • Load a new pawn from the library
    • Apply the saved material

  • Poser Ambassadors

    OMG what a dope I've been.

    So I'm happily working on the shader -- no artifacts. Then I notice that the pawn looks sketchy in SuperFly because we don't have polygon smoothing. No problem, turn on one level of subdivision. I had done that before as well.

    Oh --- no --- the artifact is back! The artifact is caused by subdividing the pawn!!!!!!! That sucks.

    So - now we know the cause as well. And I can proceed with the shader work and deal with the subdivision at some other time.


  • Poser Ambassadors

    @bagginsbill Glad to know all of this. Hmmm. I subdivided the pawn as well becasue it seemed that the texture displacement was all huge if I didn't. Eagerly awaiting your tutorials. Later this morning ....



  • You know, I've been meaning to ask where the hell you guys get these pawns from anyway?


  • Poser Ambassadors

    https://sites.google.com/site/bagginsbill/file-cabinet
    Look for and download MatPawn.zip


  • Poser Ambassadors

    I got dragged into an all-day meeting, but I'm tinkering in the background.

    This is one shader, with only ONE parameter to edit: corrosion -- 0 to 1.

    This is not a two-layer shader because a two-layer cannot be controlled with just a SINGLE number, but I will show you both ways. Two layers will need two corrosion knobs.

    What I want to know is - does this cover the range of looks you were imagining?

    alt text



  • @bagginsbill said in Comprehensive Detail: Physical Surface for P11:

    I got dragged into an all-day meeting, but I'm tinkering in the background.

    This is one shader, with only ONE parameter to edit: corrosion -- 0 to 1.

    This is not a two-layer shader because a two-layer cannot be controlled with just a SINGLE number, but I will show you both ways. Two layers will need two corrosion knobs.

    What I want to know is - does this cover the range of looks you were imagining?

    alt text

    This is stunning, @bagginsbill ... please tell me this will be released at some point! I have so many uses for a shader (or shaders) like this.


  • Poser Ambassadors

    @bagginsbill - when the mesh is subdivided, the vertex positions change as new vertices are added; if the UV's are made for the polygon surface then the result is exactly that kind of distortion as the polygon surface & subdivision surface no longer match (dependant on the topology of the mesh).

    Poser screen with no subD -

    0_1464296406386_poly surface.JPG

    I use UV Layout which can import a mesh as either a polygon or subD surface; so if I import the pawn as a subD surface it calculates where the vertex positions will be when the mesh is subdivided -

    0_1464296551164_subd surface.JPG

    Some of those loops have moved quite a bit & that seems to correspond to where the artefacts are showing up. One solution might be to add a few loops below those rounded edges so that the vertices don't move as much with subdivision.

    PS. Very cool shader as usual, looking forward to seeing more!


  • Poser Ambassadors

    First, the pawn has no UV map.
    Second, the textures in question are 3D procedurals, not 2D. They don't use UV values for anything whatsoever. They use XYZ position values.

    What may be happening is that the XYZ position being used is that of each vertex BEFORE subdivision, not AFTER. That's a bug.


  • Poser Ambassadors

    Ah, I see - thanks for the explanation!

    Yes, that would be a bug ...


  • Poser Ambassadors

    @bagginsbill Oh yes, this is axactly what I was looking for. AND thank you for the very understandable explanation on the subdivision problem.


  • Poser Ambassadors

    What happens with the normals during the subdivision?Maybe this is what goes wrong?