The ‘Render All’ function is used to force a render of all effects - that have either been created within xLights, imported via the Import Effects function or has been imported as a Data layer.
The Data Layer order renders from the bottom to top. Therefore what is on the top layer will be done last – much like painting – the last brush strokes are on the top.
Model layers also render from the bottom to top. Therefore the bottom layer will be rendered first, then the layer above it and do on until the top layer is rendered last.
However, the Models themselves render top to bottom based on how they are laid out in the Master View of the sequence. So the top model is rendered first, then the next lower model until the last model is reached.
This is important to keep in mind when you have multiple models or model groups mapped to the same channels such as whole house model group and regular models.