Flickering Rendering Problems in CityEngine

07-01-2014 07:17 AM
by Anonymous User
Not applicable
Original User: mayamardini

My team and I are working on a project to create realistic airports within CityEngine and export those textured airports and use them within Unity. We are using shape files and their respective .crc .dbf .prj .sbn .sbx and .shx files. The .prj files use the WGS 1984 coordinate system according to their real lat lon location. The big problem with this is when CityEngine tries to render these shape files, there is a sort of flickering of the images and this is even more apparent after we apply textures to these shapes.

According to http://www.3decide.com/break-a-leg/ce-to-unity-tutorial , this is because of the very large offsets in the coordinate system:
"If you export things with really big offsets, you'll probably have rendering problems, like flickering images on the final app and even the editor. This has to do with how computers store numeric values, and imprecisions that occur when dealing with big values.
The pivot points of your models will always be at the center of Unity scene. However, the geometry will be very far away from that pivot (that's the offset to the origin that exists in the CityEngine Scene). So, when you try to select your 3D models in the editor, you'll will find it very hard to actually go close to them, because Unity will focus only its pivot points."

However, even when we export all of the models with the new offset center that is in the center of our airport, the rendering is still flickering. I have been trying to find a way to reset the origin of the scene, or anything that may resolve this strange rendering problem but have been unsuccessful so far. I have also tried moving the entire scene closer to the origin of the scene (0,0,0) but this does not seem to work either.

Attached are images of a runway in both CityEngine and the exported, textured version inside Unity (.fbx format).

If there are any questions or significant specifics that I have left out, please let me know.
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1 Reply
by Anonymous User
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Original User: matthiasbuehler

hi ..

properly georeferenced data should not flicker in CityEngine ..

once exported to Unity ( with the offset set in the export settings ), all data should be near the cartesian origin, thus also not flicker in Unity.

can you post one of the shp files that cause flickering in CE ?
does that file also flicker if you insert it in a complete new scene ?

let me know ..

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