Conection of displacement and bump possible?

[Micha_cg]

Hello,

today I setup some materials with displacement and I ask me, why we have two interfaces - one for bump and one for displacement? Can be used both at the same time? And if yes, what is used first? Is the displacement calculated at the bumped surface?

But this questions are not the main reason for my post. I would like, if I could setup a bump map and use it for displacement or if I could setup a displacement and use it for bump.
The reason is - for near distance displacement is good, but if the view is changed to a far distance, it could be nice to jump to bump without to go through the texture interface again.
I try to set the map at both and disable/enable what is needed. The problem is, after reopen the Rhino file, the deactivated bump or displacement is reset to none.

Ciao,
Micha

[dalomar_cg]

Re: Conection of displacement and bump possible?

to answer the first part, Yes you can use both at the same time. I guess technically displacement is the first operation and bump the second, but I wouldn't really describe it as such. Bump needs a normal to be able to determine how it is going to affect the shading. If a surface has displacement on it, then there essentially isn't a normal until the displacement operation occurs. And if the bump did occur "before" the displacement (ie use the normal from the undisplaced mesh), then you have the potential to have some very odd shading.

As with the real aspect of you're post, I think thats a good idea. My only thing though is that I see the potential for it to be confusing to newer users. What I think might be a bit more useful than a joint bump/displacement switch, would be simple drag and drop control. With that its just dragging the map from one to the other, or even doing that right after you set one up so that its just there. To be honest, if the setups are the same, then switching from one to the other is fairly easy (at least easier than I find it in Max). Get what I'm sayin'?

[Micha_cg]

Re: Conection of displacement and bump possible?

to answer the first part, Yes you can use both at the same time. I guess technically displacement is the first operation and bump the second, but I wouldn't really describe it as such. Bump needs a normal to be able to determine how it is going to affect the shading. If a surface has displacement on it, then there essentially isn't a normal until the displacement operation occurs. And if the bump did occur "before" the displacement (ie use the normal from the undisplaced mesh), then you have the potential to have some very odd shading.

I thought, if a bump change the surface normals first, than we could get a displacement in other direction than the original surface normal dir, good for grass for example.

As with the real aspect of you're post, I think thats a good idea. My only thing though is that I see the potential for it to be confusing to newer users. What I think might be a bit more useful than a joint bump/displacement switch, would be simple drag and drop control. With that its just dragging the map from one to the other, or even doing that right after you set one up so that its just there. To be honest, if the setups are the same, then switching from one to the other is fairly easy (at least easier than I find it in Max). Get what I'm sayin'?

Yes, setup both options isn't a problem, but like I wrote, the settings of the disabled map are lost. But if I remember me right, this is an old wish - temporary disable of maps without lost. I hope, if all current bugs are fixed we can talk about wishes like this again in a near future.

Setup two textures isn't realy a nice workflow. An option called "use displacement for bump" that greyed out the bump option could be nice. Could be enabled per default.

[Micha_cg]

Re: Conection of displacement and bump possible?

... I can't use a bump to show what I mean, but I can random deform the surface like the bump should change the surface normal. Here a first quick test - grass not only straight upward.



The random deformed surface need much Rhino polygons. Maybe Joe can change the interaction of bump and displacement, so that this effect can be realized. Could be nice for thick carpets too.

An other wish: global option "disable displacement" or "use displacement for bump". Example_ if a material setup is done, but more test renderings must be done, it could be nice to temporary disable displacement. At the moment there is no way to disable displacement, it will be lost by save and reopen.

An other question: Vray support normal maps or? Can we used it a VfR too? If not, is it difficult to implement?

[dalomar_cg]

Re: Conection of displacement and bump possible?

AFAIK v-ray does not support normal maps (here or in max). Vlado has said that they are not hard to implement, but I haven't seen anything. While we're on the topic of unsupported maps, I'd love vector maps as well...makes cool anisotropy a breeze.

[Gijs]

Re: Conection of displacement and bump possible?

vector maps is already implemented in vray for max, it's a really cool feature indeed for anisotropy effects