Vray Normal map rendering vs. Mental Ray

[ln]

Hi,

 

I'm using Vray for 3ds Max and I have a question about normal map rendering. Below are two rendered textures of the same low-poly model with the same normal map. The first one was rendered with Mental Ray, and the other one below with Vray.

 

Mental Ray:

 

Vray:

 

The MR texture renders all the Normal map details uniformly all across the mesh regardless of lighting and shadows but on the Vray texture, the normal map renders only in shadowy areas while areas hit by direct light show are all washed out and render almost none of the normal map details.

 

Is this normal ? Is it possible to make Vray render normal maps the same way Mental Ray does, uniformly and regardless of lighting ? How ?

Edited May 2, 2016 by ln

[Nicolai Bongard]

You are trying to bake a texture i guess?

 

What you are seeing here is the combination of the diffuse, spec, glossy and normal of the material applied to your column. From what i can see the only thing that is similar between the material youve used in mr and the vray one is the normal map. If you adjust your vray material to be more similar to the one you used in mr, you should start to see more similar results.

[ln]

For the MR rendered texture the mesh has a simple Standard material applied to it with a normal map in the Bump slot and no more tweaks to it. The Vray render is a VrayCompleteMap and the mesh has a Vray Material with a dirt map as diffuse and the same normal map in the Bump slot. What settings will make Vray render the normal map not only in the shadowy areas but all over the mesh ? On the MR texture for example, all the pill cuts on the column have the same depth regardless of where the light and shadows are located. Why can't Vray render normals like that ? On the VrayCompleteMap, some of the pill cuts are so faded they almost don't even show at all!

 

MR material: https://i.gyazo.com/5b721c85f8c4e44f66b770f774e015fd.png

Vray material: https://i.gyazo.com/e03ec522315390b4199d6eaefe48f2a2.png

Edited May 2, 2016 by ln

[Nicolai Bongard]

Make your vray material a darker grey and use a reflection glossiness of something like 0.9 or 0.8. See if that makes it closer to what you had in mr.

 

The point you seem to miss here is that the complete map (the or at least the image you posted here) is the combination of color/diffuse, bump and reflection. So when you have a smooth/glossy material with a light color, the highlight that you can see in your mr render instead gets spread around smoothly instead of being sharp, and since the diffuse color is so light allready, the highlight is hardly visible anymore as there is no contranst to the diffuse, like in your mr render.

 

Also whenever the light is directly pointed towards your geometry it will not cast visible shadows, but when the light is more paralell to your geometry you will start to see more shadows being cast, thus it will appear more bumpy.

 

All of this is something you can observe while comparing the two pictures you have posted. So to answer your question; observe the differences and make the required adjustments in your vray setup to get a more similar result.

[ln]

Even set to a darker grey with a 30m dirt radius the rendered VrayMaterial still has pill cuts near invisible, while the MR CompleteMap with a standard material set to white still shows all of the pill cuts clearly.

 

I do get that the less light an area receives, the darker it'll look, but that is not my question. My question is about the lack of depth from the normal map not being represented on the more "lit" areas of the Vray render. How can you properly bake a high-poly normal map to a low poly mesh like that if you lose details on the areas where you have nothing to throw shade on it without having to turn everything into a dark grey mess ?

Edited May 2, 2016 by ln