Seamless Dis Maps / multiple meshes FIX!

[Ktaylor]

I have been messing with a way to take your entire character, cut it up into multiple meshes so you can further subdivide each piece for more resolution, the problem has been that each piece now has different min/max displacement amounts so when you calculate all the different maps and render them you get seam at every edge of the seperate pieces.

So what I did was add a polygon to each piece that I will want to be a seperate piece and just place if off to the side.


So when you delete part of the mesh before you create your displacement map take you Intensity to 100 % and make a Z add adn Z sub tab on the poly that you have set aside, do this to all your pieces, if you go to the ortho view and just click the mouse once you will be able to reproduce the exact amount of displacement in positive and negative directions for all your pieces and now all you maps will calculate in the same grayscale range and you wont get seams inbetween them

here you can see the 2 different maps with the same color ranges, the trick to making this work is make sure that what you define as your min/max on the seperate poly is more than anything you sculpted on your mesh or it wont work, but this should be pretty easy to do, (you could always click twice to make the displacement more if you need) also be sure and leave a row of polys on the other side of your UV boarder or else you will get stretching at the edges, you can see the poly stip in the textures and the below image




Here you can see the low res mesh rendered with Mental Ray and there are no SEAMS!


Hope this helps and let me know if you need more info on any of this, its a really straight forward approach and should always work.

[dragon4lunch]

very nice! I like how you trick the software there - very smart! thaks for sharing!

[aminuts]

positively brilliant!

[Atwooki]

Great bit of forethought there, Ktaylor - archived, and will definitely
give a good bit of trying out; thanks for the tutorial and sharing

[lemonnado]

I think I can save you some sleepless nights....

Just paint a mask onto the area you wish to detail... AND run this script:

http://www.zbrushcentral.com/zbc/showthread.php?t=28045

And to selectively poly group it... jut run the other script on another mask 8-).

Happy detailing!
LemonNado

PS:Of course the idea to save extra geometry to eliminate seams is EXCELLENT !!!!!

[Ktaylor]

lemonnado vbmenu_register("postmenu_226397", true); Yeah I saw that script a while back seems pretty usefull but this is more a of process for creating geometry sets that when recompiled will exceed the 10 million poly limit in Z brush, so if you are creating High res character that need a lot of skin texture and detail you can break it up into managable chuncks then re-assemble it with the detail of say a 20-30 million or even more poly character.

[sigh]

I am a new user and I find this technique very interesting, but confusing. Was wondering if this can be explained in better detail in the steps involved. It would be much appreciated.

[Ktaylor]

sure,

basically the problem at hand is that currently in zbrush if you want to create an entire character with a lot of detail you cant because of the poly limit in Z brush, so you have to save off your character in seperate pieces so that you can further divide them and get the poly resolution that you need.

The problem with this is now when you load each of your pieces there are different min/max displacement amounts per piece so when you calculate all the seperate maps and them apply them to your mesh and render them in your 3d package there will be seams between the pieces because the different displacement maps have different ranges of displacement being represented in the greyscale information.

So the fix I have here is to manually define the min/max amount of displacement on each of your seperate pieces, that is why there is a seperate piece of floating geometry assosiated with each piece of the mesh, so you can use the max amount of Zadd and Zsub with your brush (which is 100) and create kinda of like a clamp on the displacement values, so now all of your pieces DO HAVE the same min/max amount of displacment

hope this helps some, if you have any specific question just let me know and Ill try to make it more clear, I admitt its kinda wierd and there are a lot of things to keep your head wrapped around

the reason for keeping the extra row of uv's from the nieghboring piece is that if you dont Z brush will streatch the UVs and you will get wierd streching between each of the pieces


of coarse with the promises of Zbrush 2.5 this may become obsolete as you are allowed more polys per mesh but I suspect you wont be able to have single meshes with 20+ million polys which sounds like more than you would ever need but if you look at scan data that is used from sculpture you will find they are well in that range for capturing all the features of the character.

[spaceboy412]

okay maybe this is a stupid question but how did you create those floating bits of polygons in zbrush or do you need to do this in other software

[sigh]

sure,

basically the problem at hand is that currently in zbrush if you want to create an entire character with a lot of detail you cant because of the poly limit in Z brush, so you have to save off your character in seperate pieces so that you can further divide them and get the poly resolution that you need.

The problem with this is now when you load each of your pieces there are different min/max displacement amounts per piece so when you calculate all the seperate maps and them apply them to your mesh and render them in your 3d package there will be seams between the pieces because the different displacement maps have different ranges of displacement being represented in the greyscale information.

Ok....This part I understand fully, but one question is like spaceboy asked ...Did you create the extra polys in zbrush or from another app? As of right now, following this tutorial, I created my extra polys from another app, but if there is a quick way to do it in zbrush or what method you used I would like to hear it.

So the fix I have here is to manually define the min/max amount of displacement on each of your seperate pieces, that is why there is a seperate piece of floating geometry assosiated with each piece of the mesh, so you can use the max amount of Zadd and Zsub with your brush (which is 100) and create kinda of like a clamp on the displacement values, so now all of your pieces DO HAVE the same min/max amount of displacment

At this point, I kind of understand this part...So basically set the zadd to 100 and paint on the extra poly and then use zsub and do the same?

So after that I can begin adding detail and such to my model?

So say I completed the detail. and want to start the process of exporting everything....do I use the multi displacement maps in the plugins section? or do I create regular displacement maps in the tools menu? Also when do I delete the extra polys? in the 3rd party app or in zbrush? This is mainly the part of your explanation that I am confused about, and feel can be documented in further detail.

the reason for keeping the extra row of uv's from the nieghboring piece is that if you dont Z brush will streatch the UVs and you will get wierd streching between each of the pieces

So I only have to keep the extra row from the nieghboring piece on the map itself and not the model? This part I kind of understand but again I can use abit of help on this part.

Another question I have is when bringing it in to a 3rd party app can all the maps be put together as one?

of coarse with the promises of Zbrush 2.5 this may become obsolete as you are allowed more polys per mesh

Isthe new version made to be more memory effeicent or will you have to need an powerfull rig to achieve those results?

Ktaylor...I appreciate the help your are giving and I apologize for the newbieness towards understanding this technique.

[Ktaylor]

I think it would be best to just demonstrate it via a Zscript you can run

but to answer the qustions

Yes you add the poly planes in whatever 3d package you use before bringing it into Zbrush

You only need to use the multi displacement map plugin if you mesh has uv's outside of the 0-1 range (which they should be, you should have a uv set for every piece ideally or close to it, just makes managing all that date more easy.

and the part about the extra row of UV's is this
1.Make a tube with open ends and sculpt it in Z brush
2. create Displacement map/normal map and you will see it stretch at the ends, I dont know why this happens but it does, So to prevent it you cap your edges that you care about with edges from niegboring mesh boarders.

there are of coarse flaws in all of this but its the only way I have figured out how to achieve this

Flaw #1

since you are cutting up your mesh into pieces to acheive greater detail how do you make sure the detail lines up from piece to piece since you cant see the other piece while you are sculpting it, there are some possible workarounds but Im not really happy with any of them,( like since you have the neighboring piece you could sculpt your detail out across the seam and then save the displacement map and reapply it in Zbrush to the next piece and continue to sculpt but there are some problems I suspect with that ) so for now I just dont add any detail around the edges so I wont create any seams .