Material overlap
Hi,
I don´t know how to resolve this problem of material overlap.
The avatar is a obj. from Daz3d, with 3.0mm skin offset, the shirt have thickness collision of 1.0mm and thickness rendering 1.0mm, the belt of trouser i put thickness collsion 0.8mm and the thickness rendering 1.0mm.
First i don´t know if this values are correct, can u help me try to understand?
Thanks
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Hello Daniela. I will try and give you good explanation of what the skin offset does, add'l thickness collision and add'l thickness rendering does. To see the effect better, you should turn to Textured Surface (Thin). The thickness of the fabric is not considered for simulation, only for visualization.
I will start the fabric.
1. Every fabric has a base thickness. This cannot be less than 0.01 mm. In the image below you'll see a base thickness of both fabrics of 1 mm, which will give a total 2 mm separation between the two pieces when simulated. In this example the Add'l Thickness Collision and Add'l Thickness Rendering is set to 0.0 mm for clarity.
If I turn the Textured Thick Textured Surface on, you will see how the visual thickness fills in the void exactly from the center of the fabric. 0.5 mm to each side of each piece of fabric.
2. If I increase the Additional Thickness Collision to 4.0 mm on each piece (not the fabric itself), you see how the seam lines remain the same, but the internal space between the two pieces bloats to accommodate 8 mm.
3. If I now increase the Additional Thickness Rendering to 4.0 mm on each piece and each fabric base thickness to 4.0 mm you will see how the fabric will become thick in an even way. There will be no space between the pieces visually, but internally you have 8.0 mm space.
Conclusion on the fabric thickness settings:
a. The base thickness of the fabric is the minimum space that each piece will have when layered to other fabrics.Take into consideration that the base thickness is for each piece, so when layered that will multiply by 2.
b. The Additional Thickness Collision is controlled per each piece of the pattern and is added to the base thickness of the fabric. This does not work at the seam lines.
c. The Additional Thickness Rendering is also controlled per each piece of the pattern, but is not used for simulation purposes.
d. If you want to surfaces to be flat against each other you should have the same value for Additional Thickness Collision and Additional Thickness Rendering to make it look evenly thick.
Skin offset is the same concept but on an Avatar. The Skin Offset is the invisible space between an Avatar surface and the fabric simulation. For lose garments, I wouldn't worry much. For underwear and skin tight garments you should reduce it to have the fabric conform to the Avatar shape. Also reduce the particle distance to have more geometry to follow the curves.
Now, to the practical application of your problem
Reduce the Skin offset of your Avatar to 0.1 mm. Set the Additional Thickness Collision to a low value on all your items (0.1 mm). Make your pants a Layer 1 and freeze. Freeze your belt too. Simulate the Shirt until is well tucked in. Freeze the shirt. Set the pants and belt to Layer 0 again. See if everything ok.
Now, keep the shirt frozen and leave it like that and only deal with two pieces of garment at a time.
These articles might help:
https://www.youtube.com/watch?v=1jjAg499bQE&t=2s
Let us know how it went and sorry for the long post.
Pablo
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You need to relook at your post Pablo on this as it is not technically correct.
Go through it again and check it over, as this would be confusing to any new user > the offsets on these features all work in concert with each other, you have some maths errors and you have left out some important issues on how edges work between patterns.
Let me know if you want me to correct it for the user.
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Please ottoline. You'll be helping me, the Community and Daniela.
=)
P
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The 1st maths is incorrect (your #1 with image)
A fabric that is 1mm thick for both patterns with a collision offset of 0.0mm and 0.0 render thickness does not have a 2mm gap it is 1mm between thin surface planes.
All fabrics have a mid plane mesh surface (vertices points that form a zero thickness plane in euclidean space ) that defines the fabric plane at which all measurements take place. This also means CLO3D and MD are 100% compatible in file transfer between garment parts and projects (that they work the same with thin mesh exports). And that CG pipelines also define (thin) surface planes in euclidean space in a compatible manner so any additional thickness modifiers in down workflows on thin mesh all stay relative. This is crucial otherwise it would create an unholy workflow mess downstream in CG. For example Modo, Max, Maya, even Blender use the -1,0,1 offset scalar from the surface plane in applying thickness modifiers in the non destructive stack workflows when describing which side of the defined (CLO3D) mesh plane to set. This is important as it means both CLO3D and MD mesh and CG apps all work with the same reference surfaces in the same way. A fabric might be thought as having a mid plane surface and two offset faces (inner and outer). Thickness is subjective > based on exporting thick mesh and the accumulative values of fabric thickness plus the pattern(s) Additional Thickness - Rendering. A thin mesh export is simply a set of vertices (points that form triangular or quad surfaces) that describe a pattern piece shape. These are important distinctions. Thickness is an abstraction of how data (vertices that describe surfaces) get exported relative to the thin surfaces.
Hence the fabric surface that defines a 'cloth fabric in the CLO3D stack uses this important surface datum for downstream continuity reasons. Which mean a fabric at 1mm thick has +/- 0.5mm offset and consequently if the other pattern uses the same fabric at 1mm thick it also has 0.5mm which gives a total between pattern surface planes of 1mm. (Assuming the pattern has no additional thickness collision)
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Fabrics in CLO3D are not all created equal. This means that the physical preset and the thickness assigned to any fabric preset can vary in thickness.Scanned and tested CLO3D fabrics can have a variety of thicknesses due to their testing and measuring > if you check your CLO3D library you will see this is the case.
The accuracy of the fabric thickness is not set to 0.01 mm (2 decimal places) it is +/- 0.005mm as the thinnest fabric. which is 3 decimal places as the offset from the mid plane surface is 0.005mm either side. (+/-) or in CG speak defined by the scalar (-1,0,1) when a thickness modifier at a size is placed into a CG stack.
It's important to appreciate that a garment may have two fabrics that have two differing thicknesses and that you cannot simply multiply thickness to get gaps or offsets. They are additive.
eg:
Cotton_40s_Stretch_Poplin = 0.023 (cm) thick
0.023/2 = 0.0115 (cm) > mid plane offset ( front face of fabric/back face of fabric)
Cotton_Gabardine = 0.035 (cm) thick
0.035/2 =0.0175 (cm) mid plane offset ( front face of fabric/back face of fabric)
If you placed these two unique thick fabrics sewn next to each other - with a pattern additional collision offset of 0.0 and a pattern additional render thickness of 0.0 they would have a combined distance of 0.029 >> gap between fabric surface planes when taken too three decimal places.
CLO3D simplify this complexity between possible fabric thickness variance in any one garment, by giving the user the ability to custom set each pattern(s) additional thickness collision setting. That is important as it defines across any garment assembly a tolerance to make sure the CG cloth drape and mesh surfaces sit suitably away from each other - a function of the mesh resolution between surface faces that make up a tri-mesh or quad mesh.
An ideal approach is to consider the patterns particle mesh density as determining how close you might want to set this collision tolerance to avoid possible mesh 'poke through' between simulated elements. The default Additional thickness - Collision distance is set to a generous 2.5mm on any new pattern unless you change that setting or default setup. This means a recommended particle distance of 20mm on draped cloth patterns for quick assembly is unlikely (due to the edge length for tri-mesh) to cross over with another surface also with 20mm particle distance under typical human scale draped clothing on a bodice and surface curvature. You can greatly improve this gap tolerance between patterns by reducing your particle mesh density to 5mm so surfaces bend in collision at far greater edge (tri-mesh) resolution. So for smaller particle mesh densities you can safely lower the patterns Additional thickness - Collision below the default 2.5mm knowing the surfaces will not have poke through. So in many respects all these settings need to work in concert with each other. > Lower your collision pattern offset from the default 2.5mm @20mm mesh particle density > lowering it to perhaps mesh particle (edge) size (5mm) with say a pattern additional thickness collision down to 1mm. That would likely give no mesh poke through for layered pattern surfaces under close simulation.
There is more: Pattern edge sewing and pattern edge curvature effect how pattern seams simulate and how close you can simulate cloth.
Patterns with no curvature to pattern edges. Sewing line type set to 'TURNED'
Patterns with edge curvature to verticle pattern edges. Sewing line type set to 'TURNED'
Patterns with edge curvature to verticle pattern edges. Sewing line type set to the default 'Custom Angle'
Patterns with NO curvature to verticle pattern edges. Sewing line type set to the default 'Custom Angle'
As you can see the sewing edge type can effect how the pattern butt together at edges and how they cross over in the thick view, but note in each case the central fabric/pattern plane is controlled by the both the accumulative values of the two different fabric thicknesses + their respective patterns Additional Thickness- collision (and if applied the Additional Thickness - Rendering).
Does this matter? Yes. As you can see in the above renders these are patterns shown in the thick texture surface view. And if I were at this point to export these two patterns I could be 100% confident they would not be in collision as a thin mesh surface export. BUT if I applied in my next app modelling stack a thickness modifier equal to the one set in the fabric thickness I would get intersecting surfaces on the vertical edge. (the thin view will not show this) So this can be a great human check to carry out visually in CLO3D across your garment and seams.
This is not the end of the topic - as you can also apply to each pattern Additional Thickness rendering. Which can give you a visual change on top of the patterns fabric thickness and the patterns Additional Thickness - Collision. This is accumulative. And for that reason it matters if you mistakingly set your patterns Additional Thickness rendering higher in value than the the patterns Additional Thickness - Collision value > then export a thick garment mesh from CLO3D or that you view the model in the thick textured view - where faces would appear to overlap - causing user confusion.
I will post some more on that when I have time. The human visual check and pattern and fabric numerical checks inside CLO3D matter, when you export.
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Thanks ottoline. Great read as always.
P
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Hy guys,
Thank´s for the explanation, it was very helpfull really.
After both explation, my questions of many things just desapeared..
Now i realize that fabric are interlining with pattern and i can change if i want. (i dont even knew it)!
I´m Portuguese (from Portugal) and my knowlege of english is not the best (by the way sorry for my not so good english :D ) and my late response it was to understand better both explanation. :)
Best
Daniela
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I think the problem is not the thickness of the fabric. Just on the shirt formed a hall, fold. Fix it and the problem will disappear. I circumcise my shirt in line of sight. The first thing I would do would be to install the shirt as a trouser lining. By the way, you used layers in the simulation, you can just set the pants to layer 1 and shirt layer 0
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