When using the VrayBumpMtl bump node to wrap the plugin, the normals are not being altered.

Happens in maya.
Works in 3dsMax and Standalone!

E.g.

BRDFThunderLoom BRDFThunderLoom {
filepath="test2.ptn";
uscale=4;
vscale=4;
uvrotation=0;
yarnsize=List(0.1, 0.2, 0.3);
yarnsize_on=List(1,0,1);
}

Won't load yarnsize and yarnsize_enabled values for yarn type 0, 1 and 2.
yarnsize_enabled is always 0 and yarnsize will be set to the last value, for all yarn types.

If the spec amount is set to 1.0 this will render as expected in Maya, but the batch render will be black (zero spec). This happens regardless of what the spec color is.

A workaround is to set the spec amount to 0.99 (or lower as desired), but I thought this would be a good thing to fix on the shader internally, as there seems to be a math glitch somewhere causing this.

Right now, the shader renders very strange until a pattern is loaded. We should make sure that there’s a nice default pattern

Add a Fresnel term to mix Diffuse and specular as a dielectric

Needs to be investigated

Maya will crash if there are too many "daisy chain" connections into Thunderloom shader.

For example if I connect a file texture to the type1 spec color, this works fine (a into B). Further, if I connect a file texture to a VrayFalloff, then connect that to the type1 spec color (a into b into c) this also works fine. However if I add an additional step to the daisy chain: texture map > gamma > falloff > thunderloom spec (a into b into c into d), this will crash Maya. In other words if the daisy chain gets too long (three links) it crashes.

Work around is of course to minimize the node chain length.

This feature request was mentioned in issue #2.

Could probably use this: http://help.autodesk.com/view/3DSMAX/2017/ENU/?guid=__files_GUID_6105A0AF_BD5F_48E6_A593_188FD160750D_htm

@petermcevoy @vidarn

Gentlemen, a feature suggestion:
The VrayMtl has a diffuse "roughness" slider which goes between Lambertian diffuse (roughness=0) and Oren-Nayer diffuse (roughness=1). This has a "powdery" look to the diffuse shading which looks nicer with soft fabrics like cotton.

If this would be something that could be pulled from the VrayMtl BRDF into the Thunderloom shader (and therefore hopefully not hard to implement), I think it could visually be quite nice. Hope you will consider it.

best,
Derek

The shader does not appear in the GI render element (RE) and it is also missing in the diffuse RE. It would be really great if it could appear in the diffuse RE because then one could bake the diffuse WIF pattern into a texture map. This would open up TONS of really great possibilities for look-dev, and so.would be my number 1 wish.

Suggested by Derek Flood.

The function tl_eval_texmap_mono_lookup in vray_thunderloom.cpp is not implemeted.
This means that there will be problems when varying yarnsizes non-uniformly, such as with a changing texture. I can't find a way to achieve this sort of lookup using the V-Ray APIs.

See my question on the ChaosGroup forums for more info: https://forums.chaosgroup.com/forum/v-ray-for-maya-forums/v-ray-for-maya-sdk/76255-texture-lookup-with-uv-on-non-bitmap-textures

See the implementation of tl_eval_texmap_mono_lookup in vray3dsMax/3dsMax/Eval.cpp for how it works in V-Ray for 3dsMax.

It would be nice if the shader worked with bump and normal maps. This is particularly useful in simulating subtle wrinkles in fabric, as seen in this example (currently done with displacement)

Howdy,
Would it be possible to put up a Windows compile for Vray Next (for Maya 2017, 2018, 2019) on the Release page?

Thanks!

Each pixel would be converted to one square in the pattern. A black-and-white image could be used for the warp/weft and a color image for the yarn type.

Greetings!

I was just wondering, is there any chance we might see a front end for Arnold 5.x anytime soon?

Cheers,
-CMPX

Bug: Having zero in the bend will break the shader, meaning the spec goes black. Non-zero values (0.001) work fine. So perhaps the slider should be made so it cannot go to zero, but just a little above that.

• Diffuse amount slider (mult)
  Multiply diffuse color with this factor.

• texture gamma text field
  "texture gamma" field where the user could input the gamma to be used for all the colors. Currently they each need to be linearlized individually which takes a lot of work to set up. So having a single place to control this for all the diffuse colors would be very helpful. The pseudo code would be "pow (color, texture_gamma)" so the default value of 1.0 would leave the colors unchanged, and a value of 2.2 would linearize all the diffuse colors from sRGB (2.2) to linear (1.0).

Suggested by Derek Flood.

Allow changing the color of the specular reflections.

I've been testing the "alpha" slider that Peter revealed for me in a branch of the shader, and can say that it is really helpful for getting "metallic" fabrics like silk to look right (honestly I was not able to get silk to look right without it). So I'd put in my vote for keeping this exposed in the shader. For example, changing the alpha from the default value of 0.05 to 1 makes the spec basically uniform like a metal, rather than a dielectric material. Thus giving the "metallic" look of a silk.

I would suggest giving it a more descriptive name than "alpha" which indicates its purpose, like the other attribute names in the shader do. Perhaps you could call it "uniform specularity" or maybe even "metalness."

Specular noise gets applied in a different way when uv rotation is used.

Greetings,
I've tested to use Thunderloom with Vray 3.6 for my recent project, and it worked very well
and it was so impressive. This tool enable artists to create entirely new and believable fabric texture.
But it doesn't seems to work well with Vray 4.x (aKa Vray Next), There were error log like, 'BRDFThunderloom shader cannot be loaded.'

Would be useful, in addition to the tiling and angle parameters

The current diffuse shading is quite lacking. To improve this, we should probably look at how it’s done in hair shaders. I believe what we’re after is multiple scattering. The specular reflection is single scattering since the light scatters once before leaving the yarn.
I have found this paper: http://www.cemyuksel.com/research/dualscattering/dualscattering.pdf
which seems like a good starting point. It is referenced from Pixar’s memo on hair rendering found here: http://graphics.pixar.com/library/DataDrivenHairScattering/paper.pdf
I believe @sharktacos has a lot of insight into how this is handled in hair shading

After the program tried to show ThunderLoom Shader, the 3Ds Max program was closed.

VRay gives error "unsupported material" when exporting vrscene with tunderloom.

Tried to build a 3DS Max 2020 vray 3.6 dlo unsuccessfully. could you please release a ready build for that version combination?

The 3ds max and Maya versions of Thunderloom could perhaps be added to the Autodesk App store for easier installation. There are instructions here: https://help.autodesk.com/view/3DSMAX/2019/ENU/?guid=__developer_writing_plug_ins_packaging_plugins_packaging_plugins_html
Perhaps this should wait until v 1.0 is done?

The falloff of the diffuse component looks off when GI is enabled and a directional light is used.

The error appears to be most noticeable with the Maya lights (directional, sphere, point, etc) as opposed to the Vray Lights. I also observe that the error is only present if GI is on. The GI part confuses me frankly, but the affect of turning it off completely eliminates the error. Tested on Vray 3.5.01, 3.5.02, 3.5.03, and the nightlies for 3.6.

shirtThundeloomDiffError2.zip

gi_maya_directional.vrscene.zip

Issue found by Derek Flood.

@petermcevoy Please add the ability to rotate the UVs (enhancement). Pretty please!

This should happen after the UV scale parameters.
This would make it possible to create knit as well as woven patterns:

The Vray Diffuse Render Element is not working correctly in Maya currently. It appears to return the Raw GI, rather than the diffuse (i.e. the flat texture color).

How to compile and get the dll file in the released packages? Many thanks.

Feature request: It would be helpful to have a checkbox option under "reset yarn types from file" to "keep default yarn type settings." That way if one wanted to change the pattern (PTN/WIF) they would not lose the default yarn type settings when they loaded it in.

hey! im new in 3dmax 2015- vray 3.0, i want to use "ThunderLoom" is it possible?
I already read several post here about installation, was like Chinese :D.. i really dont know Cmake, SDK, .... how to do it

Getting frequent crashes in Maya when connecting a texture map (Maya file node) to the Spec color and diffuse color. Sometimes the error is just Vray crashing

"Error: Vray: There was a fatal error rendering the scene"

other times Maya crashes completely:

"Runtime Error! Program: C:\Program Files
Autodesk\Maya2017\bin\maya.exe R6025 - pure virtual function call"

A workaround for this appears to be to connect the textures to the individual yarn types (ex: yarn type1 specular color" ) instead of to the "default yarn type" spec Color or diffuse color.