Manipulating a bitmap and affecting bump?

[pailhead]

Note: Most controls on the Output rollout are for color output, and don't affect bump mapping. Only the Invert toggle is considered; it reverses the direction of the bumps.

Is it possible to circumnavigate this with vray somehow?

[vlado]

What do you want to do with the bump?

Best regards,
Vlado

[pailhead]

All sorts of stuff. Increase gamma, change the curve, output. Basically i like the options in the output rollout but they dont affect the bump. For example, lets say we have a brick texture. The bond is black, but the brick itself ranges from mid grey to white (various holes and dents and irregularities). I would like to crank up the curve so to flatten all the grays into white, but keeping the black and whats close to black, black.

[vlado]

Ok, I see. Technically, it is possible to derive the bump based on the actual color changes of a texture - this is what we do in Maya, for example, where all things you mentioned work for bump mapping. I'll see if I can put together a simple utility texture to do that for 3ds Max...

Best regards,
Vlado

[pailhead]

Thank you!

[pailhead]

You might want to check this out

http://www.neilblevins.com/cg_tools/...wrong_bump.htm

[trixian]

Oh yes this would definately be nice. I have been wishing for this (for max) since i began cg work over a decade ago, and has been placed on the wishlist part here back around version 1.09.
A way for the vray materials to read the gray levels of any resulting mix of maps and totally ignore the silly "mono channel" nonsense that someone added to max back in the olden days.

[vlado]

Oh yes this would definately be nice. I have been wishing for this (for max) since i began cg work over a decade ago, and has been placed on the wishlist part here back around version 1.09.
A way for the vray materials to read the gray levels of any resulting mix of maps and totally ignore the silly "mono channel" nonsense that someone added to max back in the olden days.

There is no need to change V-Ray materials at all. What I'm working on is a VRayColorToBump texture that you can plug in the bump map slot of any material.

Best regards,
Vlado

[vlado]

So you can get my first attempt here: http://www.spot3d.com/vray/misc/vray...mp_vray2_0.rar

This is currently only for V-Ray 2.0, although I can probably do a V-Ray 1.5 version, if necessary.

Extract the respective plugin in the [maxroot]\plugins\vrayplugins folder. This will add a new texture, VRayColor2Bump. Use this texture in the bump slot of materials (e.g. VRayMtl), and attach the actual color texture to it. It would be best to keep the bump amount in the material to 100, and only adjust the height parameter of VRayColor2Bump.

Note that the height is in world units, and will not scale along with an object like the 3ds Max regular bump. This is because it is actually derived by considering what would be the surface normal if the surface is displaced with the given texture (this can get quite slow with complex procedural textures, as it requires four evaluations of the base color texture).

I haven't tested this very extensively, but if you find any issues, please let me know.

Best regards,
Vlado

[pailhead]

Can you do a version for 1.5?

[crazy homeless guy]

So you can get my first attempt here: http://www.spot3d.com/vray/misc/vray...mp_vray2_0.rar

This is currently only for V-Ray 2.0, although I can probably do a V-Ray 1.5 version, if necessary.

Extract the respective plugin in the [maxroot]\plugins\vrayplugins folder. This will add a new texture, VRayColor2Bump. Use this texture in the bump slot of materials (e.g. VRayMtl), and attach the actual color texture to it. It would be best to keep the bump amount in the material to 100, and only adjust the height parameter of VRayColor2Bump.

Note that the height is in world units, and will not scale along with an object like the 3ds Max regular bump. This is because it is actually derived by considering what would be the surface normal if the surface is displaced with the given texture (this can get quite slow with complex procedural textures, as it requires four evaluations of the base color texture).

I haven't tested this very extensively, but if you find any issues, please let me know.

Best regards,
Vlado

A bit of a thread jack here, and by a bit, I mean a full thread jack for this post.

What is the feasibility of doing a plugin that would allow for the reading of ICC profiles? I find that Max's inability to read ICC profiles to be a big pain in the arse, especially when working on high gamut monitors.

[vlado]

It is not impossible; there is a LUT correction plugin planned anyways, so I guess it can go there...

Best regards,
Vlado

[trixian]

Well this is why I thought it would be more elegant and simpler just to let the material read out the luminance instead of the mono channel, and keep everything else as usual. This way there is no need to derive normals and binormals etc.
Essentially piping luminance into the silly mono channel. Why is this new node, that needs world scale bump values, better or easier to work with?
It would still be compatible with existing maps and plugins, but with the benefit of being able to actually see what is going on, and control it properly, without having to slot in new nodes into existing, sometimes very complex material trees.

[vlado]

Well this is why I thought it would be more elegant and simpler just to let the material read out the luminance instead of the mono channel, and keep everything else as usual. This way there is no need to derive normals and binormals etc.

Because it's all the same to the material; technically it's not its job to care how the bump is calculated. By the same logic, we should also build normal mapping support into it. (Now you could argue that this is exactly what we do in V-Ray for Maya )

Essentially piping luminance into the silly mono channel. Why is this new node, that needs world scale bump values, better or easier to work with?

The main reason is that giving you an extra node is much simpler. VRayMtl is part of the base V-Ray functionality and I would need to recompile the entire V-Ray plugin, so you'd have to wait until the next official update to get it. Also, this node can be used with any other material that has a bump channel (VRayFastSSS2, VRayCarPaintMtl, a Standard material etc) as opposed to us having to rework all these materials to include this functionality.

As to why the bump is in world units - partly because I like it better (often makes more sense), and partly because it's more complicated than just "piping luminance into the mono channel". In 3ds Max, each texture has separate color, mono and bump outputs; the code for bump mapping is often completely different than either the color or mono channels.

It would still be compatible with existing maps and plugins, but with the benefit of being able to actually see what is going on, and control it properly, without having to slot in new nodes into existing, sometimes very complex material trees.

This part I don't really get... that's what you would do for normal mapping, for example, no?

Best regards,
Vlado

[trixian]

Sorry, I was under the impression that max used the mono channel for bumps, not that it had yet another channel for it. Now I understand that changing this on all material types is more work from your side, but I usually judge these things purely from a user perspective. For all I know, you guys might have a modular code structure where bump logic is shared among the different vray material types. I also presumed that Vray and its parts would be completely free to define most of its inner workings regardless of how max in general did its things, so you would not need to conform to their standards if they were sub-optimal. I also don't think the existing way of handling normals is very good, and would have wished that the intermediate normal-bump node wasn't needed (as in should be pluggable into a separate "normal slot"). That is my main logic as to why I would have preferred it intergrated like I described.
But no worries, at least the separate node method is better than nothing