Bringing Models from SketchUp into CityEngine : Recommendations

Discussion created by MBuehler-esristaff Employee on Dec 6, 2012
Latest reply on Mar 17, 2014 by MBuehler-esristaff
Hi !

I've been asked to make a list of things to watch out for in the SU>CE workflow.

If your models are georeferenced and you'd like to use them as 'Static Models', export from SU as .kml or .kmz. Do not use .dae ( Collada ) in this case, since .dae does not provide enough floating point precision ('Wobble effect'). Dragging and Dropping the files in the CE viewport will automatically place them at the correct georeferenced position.

If you'd like to use SU models as assets for use in CGA, you can use .dae or .obj. Make sure these models are centered around the Cartesian origin (0/0/0) to prevent unwanted offsets when placing the assets with CGA.

.dae is an ascii (text) based format, so it can be edited in a text editor. This is e.g. helpful to edit transparency values or fix texture paths if textures are missing.
Note the default file path conventions :
./ = same directory
../ = up one dir
../tex/ = one folder up from the current .dae file path, then inside the folder called 'tex.

Same rules apply to .obj files, which carry the material definitions in a separate .mtl file.

A .kmz file is a zipped .kml file. Unzip it using any unzipper.

A kml file is just one or multiple collada files with a texture folder. Plus some metadata which specifies the georeferencing and 'height above sea level' on the centroid of each .dae model.

Make sure that every last texture you are using in your CityEngine scene has a unique name. Including subfolders of .kml and .kmz files.

If textures are missing, fix the file paths with the knowledge of point 3]

If materials have the wrong transparency values, fix them by using the knowledge of point 3]. Material transparency and texture transparency (alphas) usually are defined fully transparent or fully opaque with different values ( 0 or 1 ). This means there are different standards used in different 3d applications, thus not all 3d models directly work perfectly within CityEngine.

I'll add more points if things are missing.

Cheers !