Monday, June 17, 2013



I posted about this way back.

Spikey geometry is generally easier to make in sketchup than directly in conceptual massing.  If anyone has the answer to doing it in Revit, please share, because I have failed.  You can go so far, then you get stuck.  Revit massing loves nurbs surfaces & curvy blends.  Sketchup can't do that, has to fake curves with a smoothing algorithm, because what it really loves are triangles.  It makes meshes.

Revit topography is a mesh, but just about everything else is solid geometry.  The interesting thing is that it can take a Sketchup mesh & convert it into a solid ... within limits.  For example, make an extrusion in Sketchup.  Draw a couple of diagonals on faces. Push & pull a bit.  Save.  Now open Revit.  Make an in-place mass (or an external mass family)  Import the skp file into the mass.  Finish mass.  Make mass floors.  It works.

But if you carry on playing around, pushing & pulling, triangulating & twisting: at some point it will break.  Then you get the dreaded message as you finish the mass: "... contains only mesh geometry ... can't be used to compute Mass Floors ..."  End of story.

A year ago I failed to find a way around this. Then I was thinking about some work that Jerome Buckwell & Liam Carey presented in Auckland.  They have been exploring workflows between Sketchup & Revit for concept design with considerable success.  I hope they will forgive me for including a low-res snippet from their presentation here.  It's a bit different from what I was attempting, but it got me to thinking.

If you load the Sketchup file as a link, you can keep both applications open.  Make a few changes in skp, save, reload in Revit.  If no error, carry on.  If error, backtrack & try again.

Bear in mind that my skp skills vanished about a decade ago. But gradually I found that I was evading the error message as I cycled through the process repeatedly

Just to demonstrate that Revit converts the mesh into a true solid I changed the cut pattern of the material to solid red.  Section box cuts through just as if it were standard Revit geometry.

Using this method I managed to develop quite a complex form while keeping mass floors alive.  It would be better if I had some clear rules as to what causes the "can't compute" error.  But for the meantime the "baby steps cycle" provides a workaround.

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