topic Re: obj guidelines in ArcGIS CityEngine Questions

obj guidelines

nicholascarrington — Thu, 07 Feb 2013 21:54:03 GMT

Hello i would like to know if there are guidelines on how city engine reads obj files especially
The mtl files.

What material channels are read and how are they interpited in CE.
Polycount limits per obj.

Webgl limits.
Does the CE webgl engine stream the texures to allow for large scenes online.

I will get into more detail later but im trying to get an exsisting model of a city loaded and running
In city engine. It use to reside in unity 3d engine.
The goal would be this model residing online with some gis info attached to it.

Re: obj guidelines

MatthiasBuehler1 — Mon, 11 Feb 2013 08:53:14 GMT

Hi !

obj itself does not have a file size limit since it's an ascii format ( pure text ).

means also that you may face some issues in performance compared to a binary format such as fbx. but I like obj a lot and use it extensively.

mtl supports mostly :

- texture
- alpha
- specularity

I'd not really use it for other things. Not perfectly sure if even bump maps and normal maps and such are supported. would have to check in the obj specification.

WebGL :
WebGL scenes are can handle large amounts of geometries, but rather for offline use. Rule of thumb : don't go over 30 MB (!!!) .3ws zipped file, since it takes a lot of time to download for other people.

let me know if you have more questions !

Matt

Re: obj guidelines

nicholascarrington — Thu, 14 Feb 2013 15:00:15 GMT

Thanks a lot Matthias.

Are there any plans fora CE mesh binary like fbx? (.cem / city engine mesh 🙂 )

Maybe an export plugin to this from 3dsmax , blender, maya and so on?

I like the performance of .fbx and the Unity engine. It would help us out a bit to get
the same from CE...

Cheers 🙂

Re: obj guidelines

MatthiasBuehler1 — Thu, 14 Feb 2013 16:22:24 GMT

Hi !

I with only 1 format would exist which connects all packages, but that's an illusion since every major developer must have his own format. Formats suck. 🙂

Nothing on the horizon yet concerning new formats, but the globe's spinning fast .. 🙂

I hope Alembic becomes the new 'master' file format !

Cheers !

Matt

Re: obj guidelines

nicholascarrington — Thu, 14 Feb 2013 17:56:34 GMT

I second that Alembic motion sir! 🙂