I think I’m pretty sure this ain’t currently possible but I thought to post it to be sure.
I’m testing how well KeyShot does on an interior scene which is already way better than I expected but the V-Ray scene uses a lot of materials with ‘ior’ in it’s name. Basically it’s connected to the Fresnel IOR.
Another bitmap is connected to the refraction of the material.
This is how it looks in 3DSMax. It’s a glossiness based material but those things I can correct by inverting some maps.
From the KS manual I see I’ve a fresnel option on the advanced material but this is a on/off switch. While I need to be able to use a texture map as input. So I think I need to take a different solution for these kind of V-Ray materials.
Besides this, I wonder what values are used in KS if I put a map as ‘refractive index’. I think the index of refraction (if I look at a table) are between 0 and roughly 4. But I can’t find in the manual which values KS uses internally if I connect a (greyscale) image to refractive index. So I don’t know the actual values I’ve to put in to translate it using color to number.
In this example the textures are for the design oldie lamp with marble base and the textures look like this.
The textures with _ior in filename are used on a lot of materials from wooden floor to the kitchen cabinets. Since they are connected to the Fresnel IOR I wonder if there’s another way I can use them or just work around them.
@oscar.rottink did you ever find out any more on this? I am running across a lot of _ior files in a model I am importing as well as _ao files (not super familiar with these either) and I was just curious if you found anything out!
Fact is I’m currently testing with an interior of a hotel room since I once designed a wall size cabinet for it and came across the ior-maps again converting some props.
I think they are used if one material UV actually has multiple materials like in top example the marble base and chrome lamp. Both have a different IOR so using a texture makes it possible to give them both a different IOR.
Didn’t think of it back then but you could split the object/materials in KS but that makes the scene overly complicated. Maybe it’s actually enough to turn one of the materials into a label and use the IOR texture as a black/white image (playing a bit with contrast/value) in the opacity channel. Than you would just ‘set’ the IOR value of the label.
That way you don’t need more materials, split objects etc. I think the only renderers I know using IOR are V-Ray and Corona but even looking at their forums there seemed a lot of confusion about the map and what values it represents.
If I am correct, but I am not hundred percent sure, fresnel is basically IOR number which is index of refraction.
Basically if you want to put Fresnel IOR texture into the keyshot material, use advanced material and check fresnel box On then you use this texture as input to refractive index.
Now if you turn off fresnel in the keyshot, keyshot is not gonna use Fresnel value so you cant basically use Refractive Index and not texture map cause this function is turned OFF.
What I know from Vray, when you turn off Fresnel Reflection, you creating artificiall metal materials, these materials are not physically correct but they looks like metal. You should always use Fresnel reflection in the vray and keyshot, and you can input Fresnel IOR number to creating physically based materials.
On this website you can find values for materials, and how to match it with picture? the basic idea in vray is to put exact value and if you are using textures you have to put number first, connect image, you need to make this object rendering as simple plain color, then you match this texture color values to match refractive index value. Or the is similar way in the Vray to use something very close to color to number, in the keyshot you should put texture through color to number, and you should set up this node depending which material represent texture, so if the white color is metal you put number of metal, and black color plastic you put number for plastic in color to number node.
My recommendation to watch mastering materials by Grant Warwick
The thing is those images have different shades of grey for different parts of a mesh the material is used on. So the image corresponds to more than just one value I think more like a certain range of values maybe?
That’s why I thought maybe it works if you convert it more to a black/white image so you basically use it as a mask on labels with a certain material and put in the right number.
I’ll try to check the mastering materials tutorial. I’ve BTW mostly experience with V-Ray for Sketchup which is a bit more confusing if it’s about materials since it doesn’t have some kind of node editor/overview page. Where you easily see how things are connected.
I never seen those .ior files and I though, a well, let’s just rename a _ior texture to .ior but that didn’t work
I’ve uploaded two models which are V-Ray/Corona and converted them in 3DSMax to physical materials and exported them to .fbx
The original files are also included and I did a quick KeyShot attempt to get them done but as you’ll see it’s actually hard to get it too look like the preview picture. But it might be easier for you to try things, just be aware not all textures are actual in the node graph since I didn’t know where to tie them to (they are in the maps folders).
Especially the _ior and _reflection don’t really seem to fit anywhere. Earlier I tried to find some information in the V-Ray/Corona manuals on how they translate or what values they represent but without much luck.
It all might get easier if KeyShot will have a PBR-material node although it would still be quite different than these materials with textures as _ior and _reflection
I currently work around my way a bit with these textures but it might be interesting for you if you’ve also certain clients running into these kind of problems with commercial models they want to use.
