Strange patches on clothing in render only
nervis.wreck
Posts: 8
I started noticing this ever since I upgraded to 4.22. In preview mode everything looks fine, but when I actually render the scene some characters have these strange patches on their clothing. Using the clothing on different characters yields different results, as does changing the translucency weight of the character skin, which leads me to believe that this is a form of "poke-through". The problem is that it is not visible until render time, which means it is very hard to correct and adjust for. Has anyone else run into this issue and figured out a solution?
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Is there displacement, on the figure or possiblty the clothing? The Preview uses the Viewport SubD level for displacement, the final render the render SubD level, so the results may differ - you could try turning the Viewport SubD divisions up to match the render and see if the issue then shows in preview.
There is no displacement on the figure or the clothing and both the SubD of the figure, as well as the Viewport SubD of the clothing, and the render SubD of both are set to two in the photo provided. I have made a bit of a discovery in that changing the Viewport SubD, either up or down, of the shirt does show the patches for the briefest of moments before the preview screen corrects and shows the image you see in the photo. So it does know that there is an issue but refuses to show it in preview mode. I also had the clothing on a model which was a character with alterations. I created a Genesis 8 base character and adjusted all the settings to be the exact same as the original character, to include the maps and bump files. This resulted in the preview mode doing the same thing, showing the patches when adjusting the SubD in preview mode, but then correcting preview to show a non-problematic image. However, it also resulted in the final render not having the issue show up either. This is rather confusing and a bit disheartening as it means that I can no longer trust the preview mode to accurately show me any issues that will arise in the final render. Hopefully someone can shed some light on the situation, as I am sure that I am not the only one who relies on the preview to identify problems before moving on to the final render, and not being able to do so is miles away from ideal.
Is there a Smoothing Modifier on the clothes? Will show as a Mesh Smoothing group, below the Mesh Resolution group.
Yes, I use mesh smoothing to create more realistic looks and allow the clothing to detect the figure and adjust the collisions accordingly. I have played around with the numbers, both the collision iterations and the smoothing iterations, and while it reduces the size of the patch, the rendered image in the photo was the best I was ever able to achieve (Collision Iterations: 10, Smoothing Iterations: 5). Higher or lower values both resulted in larger patches being rendered. No values (IE: removing the smoothing modifier) resulted in nearly the entire shirt rendering with patches bleeding through, but in both cases the preview did not show the problems.
OK, so the modifier is working, at least to an extent (I wondered if it was working in preview but for some reason failing in renders).
It may not help, but if I get similar things (and there are no suitable morphs on the area/item) I look at adding a Push Modifier on the item and dialling down the default offset and doing spot renders of the affected area(s) and slowly increasing the offset until the issue goes away.
Also you may try setting Smoothing Type to Generic rather than Base Shape Matching, see if it's improved.
Or, add a Geoshell to the figure, hide the Geoshell. Select the shirt, change Collision Item to the Geoshell. Increase Offset Distance on the Geoshell as needed.