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zBrush 4R7 - Polygroup by Painted features on Texture UV?

naikjoy
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naikjoy null
I'd like to remesh a terrain with roads. Firstly I masked the roads and made em a polygroup and then remeshed em. The result was nice. But the other details of the terrain were washed out. 
Is there a way to use a painted texture for making polygroups? 
For example if I had a satellie image of the square mile I've been working on.. and I painted over with different colours the details of the terrain. Would there exist a way for me to then use that satellite painted image to automaticly make polygroups? 


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  • Eric Chadwick
  • naikjoy
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    naikjoy null
    zBrush 4R7
    As you can see by the images. Just masking the roads and remeshing everything doesn't really wield very good results. I'd like to ask if it is possible for me to do polygroups in a different way. Is there a way for me to use asatellite image of the terrain to make polygroups? or if I could paint on top of it the terrain details I'd want to have..then having those painted details be polygrouped somehow in zbrush?
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  • naikjoy
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    naikjoy null
    Is there anyone that can give me an answear? Because I can't open the stl file in Blender. I have only 2gb of ram and only 8gb of pagefile. And I cant raise it because I only have 32gb of emmc.
  • cryrid
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    cryrid interpolator
    Is there a way to use a painted texture for making polygroups? 
    For example if I had a satellie image of the square mile I've been working on.. and I painted over with different colours the details of the terrain. Would there exist a way for me to then use that satellite painted image to automaticly make polygroups? 
    If you turned the texture into polypaint data you could use Tool: Polygroups: From Polypaint
    This works better with unique colors though. If you just project the satellite image alone with all its blurry, artifacted colors then it will probably just give you a mess. 

    Are you trying to preserve all those terrain details? Remesh is meant for creating basemeshes, so it's going to wash out a lot of things by default. You'd have to work on a clone so that you can subdivide and reproject the details back onto it (or use a displacement map). If you're just trying to get it into another program with less Ram , then giving it a run through the Decimation Master plugin should tremendously cut things down while preserving just about most of the existing detail. 
  • naikjoy
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    naikjoy null
    Thank you so very much for your reply! 
    I will try and do this. 

    I'm trying to preserve all those terrain details but I noticed that once I polygrouped the road and remeshed by groups, it didn't wash out the road. So if I polygroup everything that I really need then I'm golden. Using Decimation Master it kinda washed out to some of the details. So I knew I had to go balls to the wall and do something crazy as polygrouping by texture and remesh rather by groups and set a polycount. 

    I want to make a free roam single player, multiplayer, MMO racing game based on 1996 graphics. Using different real life locations and all the cars and bikes in the world. The only thing that isn't appealing about this is the fact that cars will be 500 polys. Initially ripped from Gran Turismo 2. 



  • Eric Chadwick
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    If you want to make a game environment, the best bet will be to use the terrain feature in a game engine. Which engine do you plan to use?

    Most engines let you import height maps, and blend maps.

    You could also use a terrain tool like World Machine to edit the height map by adding roads, etc.
  • cryrid
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    cryrid interpolator
    I'm trying to preserve all those terrain details but I noticed that once I polygrouped the road and remeshed by groups, it didn't wash out the road. So if I polygroup everything that I really need then I'm golden.

    There's little information inside the roads to wash out in the first place. What the operation did was preserve the border edges/vertices of the two polygroups. Creating even more polygroups won't lead to ZRemesher preserving surface details; the borders of the groups will be frozen in place (eating most of the target polygon count in the process) but the interiors  of them will suffer since ZRemesher has fewer polygons to spread across the insides of them. If you create an excessive amount of polygroups borders for it to preserve then the operation is just going to be bogged down processing everything until it ultimately realizes that it doesn't have enough leeyway to actually remesh anything, and you're right back where you started with a massive polygon count. 

    The idea for Decimation Master wasn't to preserve every detail in your final mesh. It was to give you something smaller / lighter than the STL file so that you could import it into Blender to manually retopologize, and to preview it at camera angles closer to the final game. 

    Eric has some better advice about looking into actual terrain tools inside the engine for a better approach. If you're aiming for "1996 graphics" though then I don't think you'd want too many polygons in the terrain either way. Geometric detail was left at a bare minimum, everything else was textures and billboards. 

    https://i.ytimg.com/vi/ldLpw9TtuAk/maxresdefault.jpg

    http://www.abload.de/img/20032-monster-truck-mwwas9.jpg

    http://www.abload.de/img/28506-need-for-speed-wyk8y.gif

    http://www.abload.de/img/299405-network-q-rac-nfer4.png

    http://johnbrieger.com/img/tmnt/trackBlender.jpg 

    https://www.youtube.com/watch?v=iLuUSvAL1bw

  • naikjoy
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    naikjoy null
    Thank you so very much both of you!
    The explanations you wrote really do help alot. 
    I just need some time to think and read everything about all that you guys suggested. 

    A friend of mine suggested I use heightmaps. I tried it once but I failed miserably and I reverted back to scanned data. 
    I need to re-evaluate my options again and again. But I know once one square mile is done..then I can do the whole thing.

    The wireframe of colin mcrae rally 2 video  and World Machine seem very interesting. I'm gonna check em out :)

    I don't have any game engine in mind. I'd like to first see if I can make the location in 3D and then persuade someone to help me by showing that something is already done. But if it come to that I'll have to do everything on my own, I'd probably choose something like Unity.. seems a popular choice. 

    :) thanks again Eric and Cryrid!
  • naikjoy
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    naikjoy null
    cryrid said:

    Eric has some better advice about looking into actual terrain tools inside the engine for a better approach. If you're aiming for "1996 graphics" though then I don't think you'd want too many polygons in the terrain either way. Geometric detail was left at a bare minimum, everything else was textures and billboards. 

    True. And no I don't really want to many polygons. I used the remesher to just have a nicer topology. It actually did that. If I were to use the decimator master and manually do everything in Blender with the knowledge I have it would take me forever.

    Once I have the roads and the terrain detail in a very low poly count.. But perhaps have the roads on a higher poly count with nice topology. I could then load it all in blender and place some textures and then do the buildings, wood lines.. place trees and fences. Then polishing it and it would be done :) 


    But this is what I've tried so far. 

    Cloud Compare.. Subsample the LiDAR Data.. Save STL file.. 
    Import STL in Blender.. 
    Load the satellite image in GIMP 2.0... make alpha channel... erase everything that isn't the roads I want. Save PNG file. 
    Load the PNG file in Inkscape and make a SVG file out of it.. 
    Load the SVG file in Blender and with the modifier (forgot the name) I layed the roads on top of my low poly terrain and allign the curves ,roads on it how it should be. 

    The result was that I didn't know of a way to make the road get on the right angle without manually doing the whole road. So then I decided that if I wanted to go that way. I would have to preserve the roads atleast. Thats why I did:

    Cloud Compare.. Triangulate.. save STL file. 
    zBrush 4R7... Mask road... Polygroup road 
    hide the rest..remesh by group, smoothing, Freeze Borders. 
    Deformation - Polish by Features..Remesh by group, smoothing, freeze borders. And polish by features once again

    But then I noticed that I might aswell do the other terrain details. Atleast those details that are 50 feet from the road both sides. 
    Once I did that I would probably use the decimator or try and load it up on Blender. 

    Now thanks to you guys I know a lot more then i did before.. so I shall think of a new strategy.

    One thing that I'd like to add is that I'm ditching my ghetto laptop board with 2gb ram and intel atom. I'm waiting for a B360 chipset motherboard for the coffe lake intel. I have on my desk 32gb of ddr4 and a i5 8600k waiting for me. So soonish I might be able to do something insane. What I'm trying to say is that if I find a way to do this. I could probably do everything at once. Even if that means 32gb of ram and 1tb HDD used just for pagefile and leave the PC for 2 days and nights in a not responding state while watching on Task manager the resources used slowly going up. I'm so ambitious about this :) I really do love racing games. 
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