I hope the picture helps understanding what I want. The left side in it shows for example a street before generating the models. There I have the information about the vertices of the edges of the highlighted shape. The right side shows the street after generating the model of the shape. There I also want access to the information about the vertices required to separate the different textures of the street.
These information have to be somewhere since they are available to for example Unity (as Meshes) after exporting. I however want to access these information in CityEngine either with a main-script, or with an export-script.
Thank you for your suggestion. Your help is much appreciated.
I would very much like to stay independent of the cga rule file for this.
As for the accuracy: I would like to get those meshes with its triangles, textures and uv-mapping in a similar accuracy as I would get them after exporting the whole thing to FXB and reading them from there.
The reporting mechanisms are your main access to data on a shape. You need to use cga to put the required information into those reports. You can put many types of data into reports depending on how you break your model down.
Reports are attached to resulting shapes (the final generated shape) or shape leaf's as they are generated.
The data that is in a report can be effectively collected at export using the script based exporter. From experience I would advise you use the uuid's that are available for most things, record those into the report as the main method of data association.
Within the script based exporter you can create complex python data structures to store information extracted from those reports. The information can then be written out too, for example, xml or Jason. As python works with these quite nicely.
You could then write a parser/reader script in Unity to parse the output xml report data and do the application functions I think you are aiming to do, for shader assignments and texture hookups etc.