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bloggs
09-09-2004, 05:57 PM
could someone verify this but as far as i can remember displacement maps are for pushing the polygons out a cirtain distance from the base mesh, we all know this! but normal maps are for giving the polygon the x,y,z orientation, is this not why when everybody exports only a displacement map and exports it for use in there favorite 3d package, that this is why their final renders are not edactly like there Zbrush model, because they have forgoten about the normal maps! i know that mental ray has a dircection Map option and i'm sure renderman would probly have one.

I just thought i was important that people are aware of the importants of normal maps and hope that others can enlighten us to their uses within other 3d packages!!

anyway

cheers all!


john

Tom Pawlik
09-09-2004, 09:49 PM
Normal maps are available for a long time. Maya, Max, Lightwave and many other packages use them, i am not really sure where the problem is. Displacementmaps and normalmaps are simmilar if you want, but they are used in two different stages of the lighting and transform. Displacement is used as if it was geometry and is included in the transformation. If you use normalmapping the deformation is not so accurate (due to a lowpoly model the normalmap is bound to) and the detail only is lit.
Displacementmapping is far more accurate for animation and this is why anybody uses displacement instead of normals. Normalmaping comes to usage because of the new shaderhardware that is avaiable, but will also be replaced by real displacementmapping if the gpus get far more accurate (Possibillity to exchange values between vertex- and pixelshaders).

Tom

bloggs
09-10-2004, 04:13 PM
thanks for that Tom. i wasn't quite sure myself as i've been looking for some reading material that explains this in detail i know Nvidia had some stuff on it but i can't seem to find it anymore if you know of any links with info could you post it here?

i did read somthing about using a basic model eg a sphere and in a game engine allplying a normal map that was created in zbrush or somthing. however i'm sure for a character this would make it pritty impossible to animate as the base mesh would only be a sphere.

don't know if this is true!

Guillermo
09-10-2004, 04:50 PM
Check out ATI web they have some plug-ins for normal maping :)

The problem with normal maping, at least in Lightwave, is that you have to generate all the polycount needed for the displacement so we are talking about managing low res models subdivided to a high polycount. With normal you donīt need to subdivide the model. The normal map is very similar to the bump map, it only represents the deatil through light shadows. Normal mapping is starting to be used in games like Doom 3, see the result by yourself :)

Hope this helps!

Goon
09-10-2004, 05:24 PM
But zbrush sculpting is not limited to merely displacing along the direction of surface normals. So if a precise imitation of the zbrush mesh is going to be done with displacement mapping in a different package, wouldn't the normals of the base object need to be modified in order to correctly displace the map? Obviously somethings cannot be displayed, like overhangs, etc., but otherwise is this possible?

Also, at what point in the rendering process are normal maps applied in relation to when displacement maps are applied?

aurick
09-10-2004, 06:19 PM
Goon is correct: The very best results do come from using both displacement and normal mapping. However, such precision is not always going to be necessary; it's all about whether or not that extra smidgeon of detail is going to be visible in the final render. In most cases, displacement mapping alone will be sufficient.

BazC
09-10-2004, 08:28 PM
I once read something about coloured displacement maps that could displace perpendicular to the surface normal aswell as along it, (so overhangs would presumably be possible!?) does anyone know anything about this technology? It sounds as big an improvement over conventional displacement mapping as Normal mapping is over Bump mapping! - Baz

flingster
09-10-2004, 10:08 PM
I just thought i was important that people are aware of the importants of normal maps and hope that others can enlighten us to their uses within other 3d packages!!

anyway

cheers all!


john
for anyone using Cinema 4D...the latest release supports zb displacement maps with SPD so this should be fine.(including coloured afaik)

If you want to use normal maps or parralax shader (bump maps with texture displacement not poly) then you can use Paranormal 4D plugin for Cinema 4D.
14 day trail available here http://www.remotion.de.vu

hope this helps any c4d and zb users out there..:shrug:

BazC
09-10-2004, 10:17 PM
"for anyone using Cinema 4D...the latest release supports zb displacement maps with SPD so this should be fine.(including coloured afaik)"

I wasn't aware that R9 could use coloured displacement maps, I'l have to have a play! I don't know what app you would use to create coloured disp maps in the first place, I wonder what ZB Normal maps would do in the displacement channel!?

flingster
09-10-2004, 10:34 PM
"for anyone using Cinema 4D...the latest release supports zb displacement maps with SPD so this should be fine.(including coloured afaik)"

I wasn't aware that R9 could use coloured displacement maps, I'l have to have a play! I don't know what app you would use to create coloured disp maps in the first place, I wonder what ZB Normal maps would do in the displacement channel!?
example of R9 displacement by RGB.
http://www.cgtalk.com/showpost.php?p=1509366&postcount=127

how you get them in the first place...dunno..heh heh.

Tom Pawlik
09-10-2004, 11:59 PM
Goon is correct: The very best results do come from using both displacement and normal mapping. However, such precision is not always going to be necessary; it's all about whether or not that extra smidgeon of detail is going to be visible in the final render. In most cases, displacement mapping alone will be sufficient.

Of course that is true. I also know only one case, where normalmaps seem to deform very bad and this is when you use muscle-deformation instead of weighting/ifluence object combination.
But this is only the case if you use a lowpoly-model that is too lowpoly or that does not follow the muscles (From geometric point of view like edgeloops, etc.).


i did read somthing about using a basic model eg a sphere and in a game engine allplying a normal map that was created in zbrush or somthing. however i'm sure for a character this would make it pritty impossible to animate as the base mesh would only be a sphere.


That's the point. The most simple object to project a normalmap on is actually a cube. This technique is sometimes used for "brushes" (Not deformable Geometry for details).

Tom

BazC
09-11-2004, 08:41 AM
Thanks for the link Flingster!, don't know how I missed that one! LOL

If Red displaces in x direction, green in y, and blue in z, I would think there is a good chance a Normal map would do the job!? - Baz

Per-Anders
09-11-2004, 09:01 AM
sorry, but a normal map and a coloured displacement map are two entierly different things. trying to use a normal map for displacement won't get you the result you need. firstly a normal map is made up of "normalised" direction vectors, the normals for the surface, this means that there is no depth value, it's all 100% as it were. secondly it shows the surface normal differences between two meshes, not the direction of displacement. what you will get if you put a normal map in is a sort of flat mess.

color displacement is actually more often useful in a simpler way. once you have your head around delaing with color for the directions you can mix together rshaders to good effect, like scales, or slightly leaning over waves etc. there may even be some programs that can turn a difference displacement map out.

however the color displacement map that most people talk about wiht regards normals is the one generated by the likes of the ati normal mapper. this one is red and green, one for above 0 displacement one for below 0 displacement, this is purely to get in extra information for smoother displacement, though in itself even then it's not enough, which is where the normal map comes in to smooth the result. (btw cinema support this type of displacement map too)

BazC
09-11-2004, 09:40 AM
Oh OK , thanks for the info mdme_sadie! R9 and ZB2 are still going to make a killer combination!:thumbsup:

flingster
09-11-2004, 03:09 PM
however the color displacement map that most people talk about wiht regards normals is the one generated by the likes of the ati normal mapper. this one is red and green, one for above 0 displacement one for below 0 displacement, this is purely to get in extra information for smoother displacement, though in itself even then it's not enough, which is where the normal map comes in to smooth the result. (btw cinema support this type of displacement map too)
before we go to far off topic here sorry to the thread starter btw...
http://home.snafu.de/bobtronic/plugins/NMF_Export.zip
per does this mean you would use something like bobtronics nmf export plugin from c4d to get your nmf files (hi/lo) then use ati normal mapper to make this coloured displacement map..i just can't see any settings for this in ati normal mapper...so i'm a bit confused by it. i got the displacement map and normal map stuff...but this coloured displacement map part are they just refering to a normal map then? also is it possible to get you coloured displacement rgb from zb2? or did i just completely miss the point here..what would you do create a displacement map from zb for each colour and then mix them in c4d?

Per-Anders
09-11-2004, 05:48 PM
sorry, i think you've missed the point. the ati normal mapper generates a seperate displacement map, and that map is simply a linear map that happens to use two colour channels to increase it's apparent resolution, a red/green map.

i'm afraid i don't know of anything that produces full color rgb=xyz displacement maps.

however i posted an example or two on how to use rgb displacement in cinema in a couple of threads in the cinema forum, see if you can find them with a search.

if you want to use a normal map in cinema, you must use a normal map plugin, this will convolute the surface normals (i.e. it's simply an absolute bump map, no displacement involved). you can then use a standard displacement map together with that, the combination of the two will produce a smooth detailed surface.

flingster
09-11-2004, 08:38 PM
cheers per it was the ati normal mapper generating part i wasn't getting the rest i understand ...thanks bud appreciate it.

grrinc
09-12-2004, 11:31 PM
I am quite new to this and would like a bit of clarity myself... I am of the understanding that normal maps are just like advanced bump maps in that they do not actually alter the geometry itself. And displacement maps do alter the geometry, but at the render stage. I hope i have got this right!! Although I have yet to experiment with displacement or normal maps, I am curious to how one could accurately texture a displacement map. Would i be right in thinking that a texture created in Projection Master would be a way of accurately texturing a displacement map?? Or am i way of course here!?!?


Cheers guys (and gals)

BazC
09-13-2004, 09:10 AM
grrinc - Yup, you're quite right in every respect. I haven't got ZB2 yet but I believe displacement maps are created by comparing two meshes (usually one low res and one high res/detailed). Zbrush creates a greyscale texture map based on your chosen UV map (internally generated tiled type or externally created conventional type) to generate accurate displacement in your chosen app. - Baz

bloggs
09-19-2004, 07:54 AM
thanks people for giving us an insight. yeah i was really concerned with the detail you could get out of zbrush! things like highly detailed scales or sculpted mouth crevices on a creature would be somthing that you could have mesh over hang.

so the final verdict is that Yes you need displacements and normal maps for high detailed renders!!! and that this is why your renderings in your preferred 3d program renders my not look exactly like your original zbrush sculpture because you need both Displacements and normal maps together for all the detail!


well keep adding stuff! hopefully we could have a few more examples posted

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