From 3DsMax to Maya - Map Values

[SDSNATCHER]

Can anybody explain to me how this can be done in Maya?

When you take a look in 3Dsmax, you have the Vray Shader. It has (almost) all the same inputs as Maya has.
But there is one thing, I really can't get my head around. In 3Dsmax you have to possibility to enter individual map values.

For Example:

- You have Refl. glossiness and you put it on 0.8

But at the bottom of the shader in the maps category, you are also able to put in another percentage, let's say 15%

For what i know now, 3dsmax now uses both values. So the 0.8 is taken in consideration and the 15% from the maps is also taken in consideration.

(Am i Correct on this assumption?)


If this is correct: How can this be done in Maya? Or is this Impossible to do?
- What i thought was the solution is to set up the value in the file node. So set the Alpha Gain or the Color Gain to 0.15.
But once the map has been input, it looks like it is losing its original value that was in the Reflection Glossiness channel of 0.8.
The result is completely different then what happends in 3Dsmax.


Can anyone help me out? I have really no idea, how to get this to work.

[joconnell]

It's a mix. You'd have to set up a blend in maya between a vray colour with a value of 0.8 to represent the glossiness spinner in the max material and then use whatever mix map you want in maya with the bitmap set to 15%.

[SDSNATCHER]

Ah so it is blending between the both of them, So if i'm understanding correctly. This is doing the same thing



Can you confirm this for me?

This Blends 15% of the glossy image over the 80% grey value manually put in.

This would be the same as in Max setting the map value to 15% and the Glossy Value to 0.8 Right.

[joconnell]

Yep, say for example your bitmap was pure white or 1.0, your glossiness control was set to 0.5 and the glossiness map amount was 50%, you'd end up getting 50% of 1.0 + 0.5 so 0.75.

[joconnell]

Just as an example of where it's useful, Bertrand benoit uses a lot of black and white grunge maps to add variety to his surfaces and glossiness, they aren't very subtle on their own though. What's nice to do is set the amount of glossiness you want as an overall thing, then mix in a small amount of randomness from one of the maps. He uses this quite a bit in this max based tutorial - http://bertrand-benoit.com/blog/materialism-1/

[SDSNATCHER]

Yeah Exactly, I have seen a lot of people use this technique in tutorials. But don't see it used a lot in Maya/Vray.

It's also a pretty tedious setup to do in Maya, if you see how easily it's done in 3dsMax.

Do you maybe know if there are any scripts that automate the task? Or do i need to write something myself, should't be to hard to do.



Query all the channels of the selected shader, put them in a listarray, show them in a scrollList in a window.Select the channel here that you want to be used for the Blend. The current value of that channel will be cast in a variable, that value is used in a HSV (360,0,$var) or it will use the Vector (R,G,B)
Create a Blend node, and cast that color value in slot 2 of the blend node. Put another textfield in the same window, where you can select the texture that you want. Or keep it empty to create a empty file node. If the selected channel is a value channel put a luminance node at the end before connecting it back.
Last textfield in the window is used for a value between 0 and 1, this value will be used to set the Blend value.

If there is nothing that already does something like this, I'll think i'll give it a try.


Anyway thanks for the advice

[SDSNATCHER]

There are two more questions you maybe can answer for me;

Question 1:
In 3Dsmax I see alot of people use the Falloff node/map.
It blends two colors based on the viewing angle I think.

But Maya of-course (again) does not has this build in the UI. So I thought of blending two colors both on the end of a ramp based on the facing-ratio with a sampler info node.



Will this give me the same result? Or should i do this differently.
(I also saw that there is a node in VrayPluginNode TexFalloff that should do the same thing, but I can't seem to get it to work... Maybe i'm doing something wrong.
update: Oh wait the Vray Plugin Node does work, I think. But I still would like to know how to do it without a vraypluginnode, in a case i would like to convert a shader to another render engine.)



My second question:
Now a days you have the GGX Brdf Type, should I just set all my shaders to GGX? because it will give the most realistic result? or isn't that a smart thing to do?
Are the other BRDF types just legacy BRDF types are do they still serve there purpose?

[vlado]

But Maya of-course (again) does not has this build in the UI. So I thought of blending two colors both on the end of a ramp based on the facing-ratio with a sampler info node. Will this give me the same result? Or should i do this differently.

It depends on the mode of the falloff map. Sometimes people use Fresnel falloff mode in Max, in which case the facing ratio will not work; you'll need the VRayFresnel texture.

Now a days you have the GGX Brdf Type, should I just set all my shaders to GGX? because it will give the most realistic result? or isn't that a smart thing to do? Are the other BRDF types just legacy BRDF types are do they still serve there purpose?

I'm not sure yet. The GGX BRDF is a bit more difficult to sample and will generally produce slightly noisier results that the other BRDFs. Also, while it is definitely better for metals, I'm not totally convinced that it's better for all other types of materials (plastic, wood etc). Hopefully we'll get some time to do a bit of research on that.

Best regards,
Vlado

[SDSNATCHER]

Hi Vlado,

Thank you so much for your reply.

I didn't knew about the VrayFresnel Texture in Maya, So that is a great thing to know.

By the way, a couple of months ago I asked a question about the *.vrscene exporter from Max to Maya.
With the importer in Maya, I'm able to import most of the Vray Materials in to a Maya scene. But a couple of attribute values of the vraymtl are not coming over.
Have you guys already been able to fix this problem? If a open the *.vrscene in Notepad all the information is exported correctly out of 3DsMax.
But in Maya a couple of attribute values get lost.

(like the Highlight Glossiness, the Reflection Glossiness, the Max depth value of the Refraction, and a couple more but these are the most important)

Is this extremely hard to fix? Because now every shader needs to be checked manually to see, what the correct value is. And re-enterd manual.
Would really be awesome if there would be a fix released for this.

[vlado]

It's not terribly difficult to fix. Can you list the things that are not coming in correctly or at least point me to your original post form back then?

Best regards,
Vlado

[SDSNATCHER]

Hi Vlado, Let me write it again with the whole process described.

// My Workflow for exporting Vray Shaders that are in 3Dsmax to Maya. I first prefix all the shader names with a A001-, A002-, A003- and so on.
This way when I send over meshes as an OBJ with materials, it's easier to replace the phong shaders that the OBJ exporter creates with Vray materials that I import with the VRay VRmat Converter.
This way I can just select Phong shader starting with A001- and replace it with A001-VrayMtl once the Vray Materials have been imported. (For as far that I know there is not an easy way to send over a mesh incl. all it's Vray Materials?)

In 3DsMax I select all the geometry and rightclick and say export *.vrscene. This way Vray/3Dsmax writes out a *.vrscene holding all the shaders.
After this has been done, I convert all the Vray materials to standard materials in 3DsMax with a script.
This needs to be done, because the OBJ exporter is not able to export Vray Materials, If you don't do this you will only get the meshes over, but no Shaders / Shader assignments.
And thus you will not be able to replace the phong shaders with your imported vray shaders.
(You would need to manually re-assign the vray imported shaders straight to the mesh, and that's a really tedious thing to do)

Now in Maya I import the OBJ and get all the meshes over cleanly, and I have all the "standard" materials assigned to the correct objects.
I then go to the Vray Shelf and click the Open Vray VRmat converter. I choose the *.vrscene file and import all the materials that are in there.
I then go in the hypershade select 001-Phong and replace it by the 001-VrayMat. I do this for all the shaders.
I now delete all the Phong shaders that where created by the OBJ importer, because they have served their purpose.
Now I have clean objects with Vray Plugin Materials assigned to it. In MEL i wrote a converter that converts the Vray Plugin Node to a real VrayMtl in Maya.
The VrayPlugin Node is just a list of all the attributes, I like it to be organized the normal way. So this Solves that problem.

Until this point everything works fine, I'm getting almost all the information over from 3DsMax to Maya. I Still need to do alot of manual cleanup, with removing unnecessary nodes, but that's oke.
But what really makes my head hurt is that a couple of attributes are not coming over.
I First thought that 3DsMax was not exporting them correctly to the *.vrscene file. But after opening it with nodepad++ I noticed that the information is exported just fine.
The problem is within the Maya Vray VRmat converter.

These are the Attributes that are not coming over:

For the Vray Material it's the following attributes:
For me the most important:
- Reflection Glossiness
- Highlight Glossiness
- Fresnel IOR (for Reflection, the Refraction IOR is coming over just fine)


Also not coming over, but a little less important:
- Anistropy
- Rotation (Anitstropy)

- Use reflection interpolation
- Use refraction interpolation
- min max rate (for both reflect and refract)
- Normal Treshold
- Interp. Samples

- Also the Bump map is not being send over at all.

These are the once that i'm 100% sure of, that are not coming over.

If you would be able to fix the first 4 attributes from coming over correctly, I will be for ever grateful!
And you will be my Hero till the end of days....

[ivaylo.ivanov]

Thank you very much for the detailed information.

[SDSNATCHER]

Hi Ivaylo,

No problem at all, I found out a lot more information /bugs about the process of sending Vray from 3DsMax to Maya. I wrote a 12 page long pdf document of my research, about everything that had to do about this subject.
I wrote it for a MEL script that I was making. It's kind of a mess and not really structured, but I could clean it up. and make it a little bit more organized. Maybe you guys can use it?
If you are interested I could maybe clean it up for you, when i find some spare time.


But as Vlado said; that it probably not extremely hard to fix this bug. Do you see any possibility to get this behaviour fixxed? For atleast the 4 important attributes?
I read about nightly builds or something? a temporary version of Vray that would have the correct behaviour, it would really make my life alot easier.

[ivaylo.ivanov]

Actually most of these are supposed to be supported, but the translation is not that straight-forward. It will help if you can send over some mtl vrscenes where it doesn't work.

[SDSNATCHER]

Hi Ivaylo,

It's pretty easy to setup up. Just make a vray mtl in 3dsmax and set the value to different then the default.

- Reflection Glossiness = 0.66
- Highlight Glossiness = 0.66
- Reflection Fresnel IOR = 6.66

Then assign that material to a mesh and export it by right clicking export *.vrscene.

Go to maya and import the shader with the VRay VRmat Converter. I can guarantee you that it will say:

- Reflection Glossiness = 1
- Highlight Glossiness =1
- Reflection Fresnel IOR = 1

The same is true for the other attributes i noted under here.

(the values for the rest of all the attributes are coming over just fine)

Can you try that there?


// I removed the Refraction Max Depth, it's coming over just fine.