Simon's Graphics Blog

Work log for ideas and hobby projects.

SketchUp Cities

with 6 comments

Ray Tracey’s latest blog post has Brigade 2 renders of a nice-looking walled city scene created using Google SketchUp. The model came from this gem of a collection by “LordGood” (who evidently is a big Assassin’s Creed fan) hosted on Google 3D Warehouse.

Currently I only have a Blender exporter, and sadly the SketchUp-Collada-Blender path was producing garbage, but even the free version of SketchUp allows custom ruby plugins. After a bit of hunting around I found this OBJ exporter ruby plugin which worked very well, and now I have much nicer test meshes than my bad Blender programmer art.

The above images are from my usually-being-refactored path tracer with Preetham (et al) sun/sky. It doesn’t render as quickly as Brigade 2 (also I only have a lowly GTX 460 to render on), and yes it’s all diffuse and I haven’t exported any of the textures, and there’s no atmospheric terms or depth of field or shading normals or remote-controlled Stanford bunny, but it’s nice to have some decent public domain data to use.

I’m slowly working on a Bidirectional Instant Radiosity post (hopefully using this scene) but it’ll have to wait until work is less mental.

Written by Simon Brown

March 19th, 2012 at 10:11 pm

6 Responses to 'SketchUp Cities'

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  1. Nice renders! Looks strangely familiar :)

    I’ve been closely following your work on bidir path tracing on the GPU. Especially the two way path tracing looks very interesting. Keep up the good work and research.


    Ray Tracey

    19 Mar 12 at 11:50 pm

  2. Hello Simon,

    first of all, nice images … I really like the realistic sunlighting. How many samples and bounces do you use for the images?

    Is there any chance you can provide the already converted model in OBJ format for download?



    22 Mar 12 at 12:17 pm

  3. Thanks! It was around 128-ish samples per pixel, screengrabbed directly from a progressive render. Sun/sky sampling scheme isn’t very good yet (still investigating), so indirect is a bit noisy at these sample counts. Max path length is fixed at 16 vertices, but RR kicks in after 3 vertices.

    The obj file was pretty big, so sorry but I don’t really want to host it here. It should be pretty easy to regenerate (or generate using one of the other city models), just grab the free version of SketchUp and the OBJ plugin I linked to.

    Simon Brown

    22 Mar 12 at 4:43 pm

  4. Post it on MediaFire or something?


    22 Mar 12 at 7:26 pm

  5. Oh thanks, didn’t know such a service existed!

    OBJ file: (unmodified SketchUp export of

    Simon Brown

    22 Mar 12 at 9:22 pm

  6. Thank you very much Simon!


    28 Mar 12 at 9:07 am

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