Forgive me if this is obvious, but I still don't understand how water tight issues occur in Formit. It happens constantly with SUPER basic geometry. What makes a surface non-manifold? I've tried deleting and recreating lines and the issue persists. Pretty annoying. I've posted an idea about this previously and it's something I hope can be addressed: https://forums.autodesk.com/t5/formit-ideas/watertight-issue-resolution/idi-p/7100606
Thanks.
Hi cwinches,
Great question.
Non-manifold edges or watertight issues simply mean that the model is not built out of closed solids, and is instead a disjointed series of faces (FormIt doesn't know which faces are part of which solids). This can happen easily if you're used to face-by-face modeling, like in SketchUp.
My recommendation is to always work with closed solids in FormIt, meaning if you start with a simple surface, always extrude it to make it a solid and go from there. Then you can use advanced tools like Shell Solid, Offset solid, Boolean, etc. Also pushing/pulling faces works really well with solids as it can clean itself up better than SketchUp when dragging faces that modify the volume. FormIt definitely works best when everything in the model is solid - and it helps immensely when moving the data downstream like converting to Revit or exporting for 3D printing. You can also Group individual solids to make sure they don't interfere with each other.
In your image, I would recommend making the outer volume (white) one solid, and then making each plane of glass (grey) its own extruded volume (take the surface and extrude it 1/4" or whatever). For the white volume, you could make a large simple volume with the pitched roof, and use the Shell Solid function in the Advanced Modeling Toolbar at the top to add thickness to the top, sides, and bottom. You can do this by launching the Shell Solid tool, then selecting the front face (it will shell everything else and remove this face), to get the volume I see in your image. Then, because it's solid, you can simply drag the side wall to eliminate it as well, but still keep the rest of the white volume solid.
You should end up with no red non-manifold lines if you have that diagnostic option turned on. Moving forward, your model will perform much better!
Hope this helps, and feel free to reach out here or via DM if you want me to take a stab at fixing your model.
Creating solid geometry in FormIt shouldn't prevent you from using by-face operations in Revit, and also shouldn't adversely affect operations like Solar Analysis. Have you tried it? Is there a specific file or example that's giving you trouble?
Solid modeling in FormIt is recommended specifically with Revit in mind. Although the FormIt > Revit converter handles nonmanifold geometry better with our latest Revit 2018 converter (https://formit.autodesk.com/page/download - scroll to bottom), it can still throw errors and lose geometry if your geometry is not solid.
If you prefer to model 6 faces of a cube independently, instead of extruding a surface into a volume, you can do that too and FormIt will flip faces and merge edges into a solid. You can confirm this by turning on Back Faces (DB) and Watertight (DW) diagnostics. But modeling this way, especially with more complex forms, is more likely going to cause the trouble you're seeing: nonmanifold geometry that might not convert to Revit anyway.
FormIt is a solid modeler and that is not going to change, for reasons like what I've mentioned already (better for downstream operations, and results in a more robust modeling kernel). Give it a try, and hopefully you'll begin to see why solid modeling works better - and let us know what specific issues you run into. Before working on FormIt, I was an avid SketchUp guy, and I resisted solid modeling at the beginning too. But once I realized its power (super clean push/pull operations, shelling, booleans, downstream compatibility...), I never looked back.
