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Displacement, Normal and Bump map questions

ZBrush Usage Questions
#1

I’ve finished modelling a character and created a displacement map. Some of the details are not “clear” enough to show up on the displacement map.

1- Should I create a bump or normal map? I tried applying a normal map on the displaced character and I can see more pore details but it seems to increase the detail that is already there, is there a way to only add more detail?

2- I also read that I could “paint” a bump map but I already have the pore detail modeled, is there a way to transfer that detail to a bump map automatically?

3 -And what about this technique:
“What you would do is sculpt your high resolution model and create a normal map for it. Save the tool so that you can come back to the high resolution version later if you need to. Now switch to a medium subdivision level and delete the higher levels. Create a displacement map. You’ll now have a displacement map for medium frequency details and a normal map for high frequency details.”

Is it a good idea? Use displacement to Subdiv 5 and use a normal map for Subdiv 7?

4- Finally, how do I render a normal map in max using Mental Ray? Placing it on the bump map?

#2

anyone?? please?

#3

I think you should a pic of your mesh in ZB, the map it generates and the export options (if you are using MD3) first. Otherwise we are working blind here.

Also it may just be that your mentalray settings are not correct so please post those as well.

#4

Painting bumpmap in Zbrush does not make too much sense, if you ask me. If you already have a normal map, which is addressing each and every normal in the mesh, why do you even need a bump map any more? I do not know Max, but I do know XSI, which also uses Mental Ray. Normal map does not have a separate normal channel. You have to plug it into the bump map channel and apply it on the tangent space.

Inside Zbrush, there are not many options to change the intensity or detail of a displacement map. But if you use Photoshop, or CrazyBump (which is exorbitantly costly so it is less likely that you’d get it just for this purpose), then you can easily enhance detail of the displacement map using the same.

Using both normal and displacement map on the same mesh considerably adds to the render time, but if you must do it, then put the very large details on the displacement map, and the very fine details on the normal map, because displacement map is no good for fine detail, unless we’re ready to accept very long render time.

If I were you, I would bring the subdivision down to a level where some basic deformation is showing, but the mesh is not too low poly. Then I would delete lower subdivs and bring this to Max. Raising the subdivision to make normal map actually makes no sense, because since you cannot really use the high poly mesh for rendering, there is no point in generating a normal map that would possibly support that high poly mesh. It is a good technique for polypainting though, because low res mesh still looks good with high res. texture.

Hope that helps!

#5

Displacements - Low / Medium details.

Normal maps - high level details

Bump maps - very tiny details.

People underestimate the usefulness of bump maps just because normal maps exist these days. But they’re just as useful, more-so these days as they combine nicely with normal maps for getting the super fine tiny details, where having the directional lighting features of normal maps would be overkill or not even be seen.

If you want to paint bump maps in ZBrush, just make a new texture, then change the Material to bumpmapviewer, then paint grayscale onto your model (or clone the model, remove the polypaint and do it that way. Though you’d get better results at such fine details by using methods to paint onto the new bump map texture you just made, itself and not colorizing the mesh, as you’ll be painting details that are much finer and smaller than the polygons you have.

Just because you can have millions upon millions of polygons, doesn’t mean you need to. Pores in the skin, slight bumps and fine texture on a model, don’t need to be done with polygons or normal maps. Let them detail with the other details. You’ll find it better later, as you can easily tell your software to fade the very fine bump map details out at a certain distance when they wouldn’t be visible anyway.

#6

I know this is not the most relevant thing that could be asked here, but in certain applications, such as XSI, there is no separate port for plugging in the normal map, hence the bump slot has to be used. In such softwares, how does one use normal and bump map together?

Also, is there a good software for making bump maps? CrazyBump or PixPlant make everything else but that. I know a very good bumpmap will always requite some hand painting. But if the basics are laid out well, that can be a great help. The displacement map from CrazyBump is not really usable as bump map even at a high level of detail.

#7

Pretty much anything is ok for bump maps if you use them in my above mentioned method. The detail will be so fine, it’s highly unlikely anyone will even notice pin point details. It’s more about adding that little bit of extra chaos and unpredictability, just taking the CG edge off a model. When I look at the mess of ash around my ashtray, I don’t see the direction the light is falling on it, or the way it’s shadow looks. I just see little particles of ash. The eyes don’t really care for perfection if you throw enough randomness at them.

Or something like that, lol. ZBrush can do just fine with bump maps, Photoshop etc. too. Really doesn’t matter, if you stick with them just for the very fine details, you’ll be ok.

As for Softimage, I don’t know. It’s not a rule or anything that you HAVE to use both. It’s more just a choice. I personally would use both in some situations, but you certainly don’t need to. Maybe in Softimage there’s a way to merge them or something. Pretty sure there is, when I’ve used it I’ve never had any problems using both normals and bumps together.

#8

So, when you used Softimage, what procedure did you take to use them both? I am not feeling I have to, but I just want to, exactly for the reason you’re preferring it.

#9

I really can’t remember, I rarely ever rendered out from Softimage and mostly just used it for modeling, while rendering etc. would be done through Lightwave. I’m trying to think now how I went about it, but cause of using LW nodes so much recently, all I’m seeing is those instead of Softimages’ Render Tree layout. I never really got into the Render Tree though, so it can’t have been anything too convoluted, otherwise I wouldn’t have been able to do anything.

#10

Hi i am having problems using displacement maps and bump maps together. Here is my problem. It looks like the bump map is being rendered under the displacement map.
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