Tuesday, April 24, 2012


It's shocking to think that I spent over a decade putting in at least 20 hours a week on Acad, and now everytime I open the programme up it feels like punishment.  Part of this is fading memory, part is the different habits that Revit instills, part is simply that Revit is so much cleverer.
So why did I switch back for a whole weekend ? 

Try as you may, Revit modelling tools struggle to make decent sanitary ware.  If you look at my review of American Standard Revit families, it's clear that the ones that use CAD imports are more convincing.  In my view this is not really a weakness of Revit.  The modelling tools are very effective for construction elements.  They're user-friendly,  Sketch Mode is great, (you can back-track any time you like and rework your profiles) and the whole approach lends itself to parametric control.  It's just that AutoCAD solid modelling is more effective for certain kinds of shape.  Sometimes, different is good.

So I am making the effort to re-acquire some fluency in AutoCAD.

The starting point was a mesh created by our visualisation guys in MAX.  Looks great in their renders, but not so smooth in Revit.  My approach was to create closed polylines and loft them.  There is a great tool for rounding off edges, and you can subtract one solid from another.

I struggled with the UCS for a while, but then I remembered UCSfollow, which speeded the process a little.  I longed for the simplicity of reference planes to guide the symmetry.  But I kept going and managed to make a reasonable pan for my WC. 

Looks much crisper in 3d than the mesh, but for orthographic, nothing beats masking regions and symbolic lines.

For the seat and the cistern I dug out a "rounded rectangle" family from my Pillows Post.  Parametric radius corners !  Now this is where Revit excells. 

One Family Type for the cistern

And another Type for the Seat

Rendered up together in Revit, my family comes out much crisper than the mesh version.  But I'm not quite happy.  It's good enough for most purposes, but when I downloaded a better reference image I realised that my form is missing some subtle curvature.  I could do better, but not sure when this will make it to the top of my to do list.

Some of you may be asking why I'm going to all this trouble.  Why not just use a simple generic toilet in the drawings and specify the model number ?  Isn't all this 3d detail killing the processor ? 

Well it all depends.  If you've got 500 toilets in the project you probably want to keep it simple.  If you only have 4 or 5 and it's high end work with an Interior Design component, detailed 3d Revit families can really help. 

So why not let the manufacturer do it ?  That would be great, but this particular manufacturer doesn't have even 3d CAD downloads so I made the effort.  I'm also thinking that those of us with the  capability and the inclination can set some benchmarks for manufacturers to aspire to.  And if I publish my efforts maybe someone else can contribute comments/improvements/alternatives.


  1. It looks great, but seams like a basic shape, so why can't you make this in Revit..(it's not clear tot me)

    1. Hi Arno

      Good comment

      It's the rounding of the edges that get's difficult. You can put a void sweep around an edge and this works fine of the faces meet at 90 degrees, but in this case the slope of the sides & the front are slightly different so you end up with an error message if you try to get a smooth curve between these surfaces usint a void sweep.

      The best I have been able to achieve in these circumstances is just to cut a slight splay off the edge, not a smooth curve.

      But you are right, I probably should have chosen a clearer example. But this happened to be the one I needed for a real project. I thought I could use the mesh from 3d Max, but this was disappointing. I knew that rounding off the edges was going to he hard to achieve in Revit so I decided to experiment with AutoCAD solid modelling. Was a long time since I used AutoCAD so this seemed a good chance to start with something fairly easy.

  2. It seems to me we could get close with the mass editor. It's a shame these tools aren't available for Revit. This of course is probably where Inventor and Solidworks excel over others.


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