Hitting the target

You may have seen a nice Simplebim dataflow that does amazing things in a demo or in one of Gio's videos. Then you have tried to do the same using your own models, but were not able to make it work. If this has happened to you, the reason has most likely been the target(s) of the dataflow steps.

The ‘target’ of a dataflow step simply means the objects that are used by that step. For example if you generate wall surfaces for rooms the targets for this dataflow step are the room objects and the wall objects, which put together produce the wall surfaces for the rooms.

The thing is that the object classes are almost never good targets. For example not all space objects are rooms and not all wall objects ‘create ’ room surfaces. And if you run a dataflow step with bad targets, the step won't produce the results you expect. Dataflows are very powerful, but they are not magic.

So, if object classes are not suitable as targets, how can you create a good target? There are 3 basic methods for this in Simplebim.

1. Manual. This is the easiest way by far because you can just drag&drop objects from the 3D window into the target and run your dataflow step with the 100% correct target. But this comes with a price because drag&drop can be laborious with large models and you can use the target only with the current model or new versions of the current model. The dataflow itself can also become heavy, because your selection is internally stored as a list of GUIDs (global IDs) and a list of, let's say 10 000 GUIDs can already be a bit slow to load and run.
2. Rule Based. In this option you create a rule based group and use the group as the target. It may take some time for you to figure out the rules that select the correct objects from your models (and preferably works with other models as well), but once you have the rule figured out it is very efficient to use and the rule can even be re-used in other projects. A challenge with this approach is that coming up with a ‘universal rule’ may be difficult and fixing rules to work with one model may break something that already worked with other models.
3. Hybrid. The hybrid approach brings together the best of both worlds and it is explained in detail in this other post. But the essence is that you first create a rule based group that does the heavy lifting and then add/remove objects from the group using the manual method.

Once you understand the importance of using the right dataflow step targets and master the related skills in Simplebim, you will have no problems adapting dataflows to your own models and processes.