3D Modeling Existing Environments

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  01 January 2013
3D Modeling Existing Environments

What's the most efficient way to model an entire city with high resolution textures, accurate vertically (elevations) and horizontally?

Thanks!
 
  01 January 2013
Hi,

You should definetly look on to learn about photogrammetry techniques for vfx, this is a really useful method of accurately model buildings, props or even cities based on calibrated photos sharing the same conversion points in 3d space.

I remember having used this technique while working on a shot of jack the giant slayer. Many images were taken from a helicopter, then the images were calibrated, and the city was modeled for matte painting based on the point cloud generated from the camera calibration.

To learn more about this, I really recommend you Paul Mcwilliams cgworkshop on cgsociety, It actually explains the whole photogrammetry process!

you can also take a look at something called "matte painting toolkit" plugin for maya.

I hope this helps!
 
  01 January 2013
I agree with manuqc, photogrammetry can get you a long way. I used the exact process describes above to reproduce some existing environments on my last film project, an it was very quick and gets great results.
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  01 January 2013
If your doing a still image try to find Lidar scans of buildings.
or build them yourself using Google building maker
http://www.sketchup.com/3dwh/buildingmaker.html

or from scratch using Zbrush.
http://www.pixologic.com/zclassroom...jection-master/

keep in mind you may only want to use high resolution geometry and textures for those buildings that are near the camera.
Anything in the back ground and further away will not matter.
If you don't you'll end up with a really heavy scene that will suck up lots of ram to load and render. It will also slow down your render times.
You may want to look into LOD (Level of Detail) Object and texture replacement at render time also.
In a nutshell your tell the software, if Object A is X distance from the camera use a lower res version of the object. As it gets closer to the camera it loads in a higher detail object at render time. That way your scene still is manageable to load and work with.
You may also want to look at Ptex textures. I know they did a lot of the building scenery in "Inception" with Ptex.
 
  01 January 2013
Originally Posted by VisitorfromArea51: What's the most efficient way to model an entire city with high resolution textures, accurate vertically (elevations) and horizontally?

Thanks!


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  01 January 2013
Probably the only way is to do 3D scannig of the city. The problem is that those scanners so far has been mostly used for just streets. Architectural reconstruction of historic buildings and other experiments. The problem is that they generate too much of a dense points cloud and it remains to be seen how it performs with very tall buildings, since those laser-based scans lose performace beyond a certain distance. It is probably the last frontier in GIS technologies, real city 3D scanning.

http://city.csail.mit.edu/
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Last edited by Samo : 01 January 2013 at 01:38 AM.
 
  01 January 2013
Another method I suggest, is to look at the google maps service, I believe it offers 3d elevation models for some cities, and as was pointed out before, the sketchup plugin to build the buildings needed... I would do this if you can't access accurate photos for photogrammetry.
(maybe even a mix of both depending on what I find..)

with those 3d models from google you can quickly dress up a city, yeah the geo might be crappy...etc etc, but you dont need ultra high res modeles for everything neither (specially not for matte paint, also you can clean the geo, which might be quicker, than starting from scratch.....depending...). And if you need well then you can go case per case depending on the shot and proximity to build something more detailed.

As for the suggestion of using zbrush projection master, I would have to disagree. This technique although as cool as it might look, doesn't have its place imo, in a full city modeling task. I myself would use this technique only for ultra close up shot that requires complex ornament modeled... then yeah you can get your displacements, etc... even so there is a lot
that can be taken from high quality photos or surface scans.

Also for videogame modeling, to get a highres model, dont caring about geo as it would simply serve for normal baking. Other than that I dont find it "truly" useful.

I would suggest to take a look at: www.surfacemimic.com I have purchased some scans myself , and was blown out with the quality of the displacements... really cool stuff

Last edited by manuqc : 01 January 2013 at 05:44 PM.
 
  01 January 2013
Hey man,

You can lift the 3D building from Google Earth using an openGL capture. I did it a long time ago, and the geometry wasn't too bad. A few filters to remove the triangulation really cleaned things up. The software was called Ogle, and I had to use it with an old version of GE. You can also download individual buildings from the Google Warehouse.

I used a bunch of buildings from NYC as background props for a personal project a long time ago. I've still got the OBJs of the captures if anyone's interested in having a look.

-AJ
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Last edited by AJ1 : 01 January 2013 at 11:27 PM.
 
  01 January 2013
Thanks

Thank you everyone! You've been incredibly helpful.
 
  01 January 2013
Originally Posted by AJ1: I used a bunch of buildings from NYC as background props for a personal project a long time ago. I've still got the OBJs of the captures if anyone's interested in having a look.

-AJ

I'm very interested in a look at that. I've never heard of an OpenGL capture. I googled that and found the results a bit... confusing. Which one do you use?
 
  01 January 2013
I agree with the photogrammetry suggestions, it's quite easy to get good results. Laser scanning is great technology but I don't think that it's really suitable for this.
 
  01 January 2013
Hey Manuel,

Concerning the camera calibration and point cloud efforts, can you recall the amount of manpower / time it took (days, weeks, months)?

Originally Posted by manuqc: Hi,

You should definetly look on to learn about photogrammetry techniques for vfx, this is a really useful method of accurately model buildings, props or even cities based on calibrated photos sharing the same conversion points in 3d space.

I remember having used this technique while working on a shot of jack the giant slayer. Many images were taken from a helicopter, then the images were calibrated, and the city was modeled for matte painting based on the point cloud generated from the camera calibration.

To learn more about this, I really recommend you Paul Mcwilliams cgworkshop on cgsociety, It actually explains the whole photogrammetry process!

you can also take a look at something called "matte painting toolkit" plugin for maya.

I hope this helps!
 
  01 January 2013
Originally Posted by wancow: I'm very interested in a look at that. I've never heard of an OpenGL capture. I googled that and found the results a bit... confusing. Which one do you use?


I'll second that motion.
 
  01 January 2013
Yea, Google doesn't like people doing it, and it looks like its been bumped from the search results. The software was called OGLE, and the site seems to be down.

click to view fullsize





-AJ
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  01 January 2013
3D Ripper DX

Found 3D Ripper DX does basically the same thing, capturing textures, etc. though I think you're right when stating google doesn't like this.

I found a company that can complete aerial surface scans with textures, turn-around time extremely short. Will be looking into that more.

Thanks for all the great advice!

Originally Posted by AJ1: Yea, Google doesn't like people doing it, and it looks like its been bumped from the search results. The software was called OGLE, and the site seems to be down.

click to view fullsize





-AJ
 
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