There have been a few interesting developments recently, both here (e.g. The Lightmapper addon) and with my work, that have encouraged me to revisit my semi-automated Revit-Blender-Bake workflow. I thought I’d share some thoughts here and see where the discussion goes.
Firstly some benefits to this approach, i.e. why I use it:
- The realism of a model with the sun shining past columns onto floor slabs is powerful. Even with a single sun lamp and relatively few samples the balance of looks and performance is better than anything else I have been able to find.
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By automating the import, tidying up, unwrapping and baking, it can run happily on some server and the end user only sees the nice result. Unaware that it took hours just to unwrap the meshes.
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Turning off Collections with number buttons is fast and easy. Changing sets/layers in other software not so much.
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I have control over the model, so can adjust it easily, e.g. by deleting/hiding all of the light switches. Whereas other methods require going back into Revit, changing settings, then re-exporting. Though I do lose the Revit grouping, so sometimes that is still the easiest way. I rely on searching for strings within names, using the Outliner.
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The fly mode in Blender is excellent for walking up and down stairs or floating through floors. Other software has more or less caught up on that over the years, though Blender still gives me more flexibility and is the only one where I can jump!
Now for some of the challenges:
A. Only SmartUV unwrapping seems to give decent results for the baked lighting. It is single threaded and terribly slow. You can’t always export low-poly meshes from Revit because, for example, at low resolution all of the smaller pipes in our models are reduced down to 1D lines and therefore are not visible in Blender. Pipes are a particular problem actually, as the meshes carry a lot of vertices from Revit.
B. Once you are relying on accurate lighting, then have a problem with darkness in rooms where there is no natural light. So I end up baking second light map for artifical lighting and maybe they haven’t been modelled properly (or at all) until quite late in a project. So then I fall back on AO and simple shaders to create a reasonable-looking situation in basements etc.
C. Unless the building is particularly small, the file size quickly hits 1GB with a few 4K image maps (necessary for detail). Not a massive deal nowadays, but still a bit heavy to share easily.
That’s a lot to kick off with! Hope it leads to some interesting discussion. Hopefully somebody out there has a few ideas to help with A-D.