How to detect changes in a model between two sessions



I’m using SU to perform radiation calculations in large developments. As part of the workflow I would like to be able to analyse different scenarios. My workflow at the moment is the following:

1 - calculate a ‘shading mask’ for the points of interest. This shading mask contains also information about the surfaces that cast the shades such transparency, temperature, etc.

2 - the shading mask information is all contained in an object. I use ruby marshal to dump this object on a file.

3 - perform radiation calculations for a specified time interval

4 - if I close sketchup and open it again because I need to analyse a different period, I load the marshal file and perform just the radiation calculation because the geometry information is already in the file

5 - however, if I have to analyse a different scenario, because I have added shading, or I have changed the properties of some surfaces, I need to re-run the geometry calculation again. This can take even a few hours.

It would be great if I could detect only the elements that have changed in the model and use this information to avoid having to rerun everything every time.

Is there a way to do this?



I already replied to your similar post at SCF
see here, re: using a time_stamp attribute…