Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I don't use Designbuilder but it looks like you just change the "Layer after which the internal source is positioned" number, as described here.
This obviously restricts you to an internal source between layers. To replicate the source being embedded in a layer, I would simply divide that layer into two (same material, 1/2 thickness each) and place the internal source between them.
