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DMclean

Polymesh Problem...

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Hello all,

I've got a model that has parts that were made as smooth objects, and I now want to "degrade" said objects to poly meshes for exporting and reworking in Maya. I ran into some weirdness with the way the meshes were coming out so decided to investigate with some slightly simpler shapes and came up with the following...

Note what happens with all the versions where I wanted odd numbers to the facets in the circle. The facets created on the sloped faces are split between the lines of the vertical faces.

Any thoughts on why this is happening or whether there is a way to work around it?

Thanks in advance,

 

Douglas

 

PolyMeshProblem.jpg

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Douglas,

The only thing I can think of is that the algorithm that is doing this goes face by face and doesn't consider the adjacent faces.  Firstly, how did you create the original objects?  Revolve?

When the "No Grid on Planar Faces" is turned off, I note that there is a point forced where the seam of the revolve is.  If I turn that option on, it goes away.  Second, try upping the angle tolerance to the point where it breaks to the next value.  for example, 5 faces around can be as high as 124.

One thing to note, using the revolve, the "No Grid on Planar Faces" probably had the most effect.  but weird thing, my aberrant points prior to selecting this option are not in the same place.  This is Why I ask how you derived the original shape.

¢£

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Have tried joint values, but still get the problem until the object has the even number of faces when it goes polygonal...

 

Edited by DMclean
Clarification

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Chris,

Thanks for your tries. Spurred me to check a few other things and...

I took the 6 sided values (90 degrees) and halve it to 45 deg which produces a 12 sided object with no problems...but if I drop the value to 22.5 deg to produce a 24 sided object the problem comes back...

The desire to produce specific numbers of sides comes from the fact that once I get back to maya I want to work out nice quad shapes with some intersecting object holes so that when the whole thing is subdivided i get nice neat shapes that nest together, and I needed a number of sides that would be divisible by three... so I may just wind up going with the 12 sided...but it seemed to me that the tool should be ale to generate whatever number of sides I wanted and keep seams neatly aligned with nice planar faces, which it does... just not all the time..

Curiouser and curiouser...

 

Thanks,

 

Douglas

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Douglas,

Ok, using your construction method, I am seeing the same results.   Of which, the seams appear to have no effect.  Doesn't make sense to me either.

 

If these are the types of shapes you are looking for, I think I would use the Revolve/Faceted tool do directly derive your shapes with the poly count you want.  Translating from smooth to faceted seems like extra unnecessary steps.

If on the other hand, you are only showing these shapes as a "dumbed down" example of what you are really trying to do.  Not sure what to tell you without seeing the specifics.

 

You may want to email tech support directly on this, as it does appear to be odd behavior.  And the forums are kind of unmonitored these days.

¢£

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Hi Chris,

This allcame about because I had a model that I made a year ago which I rendered and used just within formZ, so I just used the smooth model, and that was fine. Decided that I wanted to re-work it and render it in Marmoset Toolbag, so because I needed to UV it,  bake normal maps etc, I wanted a polygonal model to work with so I could get a hi-res and lo-res version fairly easily, cut the lo-res for UV’s-ing etc... rather than rebuild from scratch I thought it would be interesting to try to convert the original to poly, which led me to the problem.

in fact if I had been thinking about this when I built the original model I probably would have done the reverse, building a low poly first and then sub-div for more resolution.

The example I showed is a slightly dumbed down version, but revealed the problem so I could try and show several iterations where it did and didn’t occur.

I have managed to get it working for this case by choosing resolutions that did work, though I would have liked to have had more choices at my disposal.

thanks for confirming that the problem exists on other systems, and it wasn’t just me and mine.

All  the best,

Douglas

www.rainbeau.net

 

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Another example of my Polymesh Conundrum... Box, 2 edges smooth circular bevel. Polymesh with Normal Angle Tolerance set to 32...

985152924_ScreenShot2020-10-01at8_56_37AM.png.a9371ca3065a57725e9570c4656da2a8.png

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I would suggest exporting as obj the smooth mesh without attempting to reduce the polygon count in FormZ. Then import the obj into Instantmeshes https://github.com/wjakob/instant-meshes and reduce the poly count there. You will be able to retain a fairly good all quad topology, which is easy to UV in Maya or a UV editing application such as Rizom UV. 

 

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