Tuesday, October 25, 2011


Post number 3 of my pumpkin carving competition entry.

OK so the first image is a nice diagram that Wil sent me. It explains the derivation of the formulae in his original family. Now I understand better what he was driving at.  Probably more scientific than my "Bulge Factor" approach, but I'm going to persevere for the moment with my nested profiles.  In fact I'm going for a "Five Stack" this time around.

You may notice that the profile family looks neater now.  I've got the whole "select-filter-copyrotate" routine down now. But that's probably a separate post.

Using 5 profiles is a bit more hard work, but it gives me more options for sculpting the shape.  This time I want to focus on a more realistic, organic looking pumpkin.  So this represents the opposite pole to that whole Doric, pure-geometry approach to Design.

Now I'm getting a rounded volume with a depressed centre. But it's still too regular.

I can play with the render settings.  Give it a bump map.  This one is based on the Leather Fabrics, but with the depth of the bump map cranked up.

Looking at images of pumpkins I got the feeling that my segments were too regular. So I made another profile, being deliberately sloppy with the setting out.  This is better, but I need to give one or two segments an extra bulge.  I also reached into my bottom drawer for a render texture image that I made a while back to simulate old walling  (we do resorts that capture the feel of a desert village, see this link :  Bab al Shams by GAJ  )  It has a large-scale blotchiness.

Rendered up, the result is starting to get there. The stack of 5 profiles also gives more control over the stem.  I can keep most of it thin then just bulge out quickly at the base.  No way to achieve that with only 3 profiles. Would be better if it curved to one side, but that needs a different family with profiles swept along a path.  While I am busy messing with the render settings I sneaked in a background image from the bit in Cinderella where the fairy godmother transforms the pumpkin into a carriage.

I haven't used the background image in renders much before.  I like the way the automatic sky responds to different times of day.  Flat images of the sky tend to look a bit ... flat.  But perhaps there is scope for using images in a more diagramatic context.  It's OK to be flat when you are not trying for that ultra-photo-real effect.

In the end, everything we do is a diagram, and sometimes a simple thumbnail sketch is the best way of communicating an idea. We should spend more time thinking about what is the BIM equivalent to this.

  The massing tools are one approach, but there must be many others.  Just because it's an intelligent 3d model it doesn't have to be so complex that you can't see the wood for the trees.  For example, a while ago I made a Revit version of one of Corb's simple diagrams.  "Less is more" as a cigar-smoking German once said.


  1. Hi Andy,

    I like what you did with the doric column. I converted my family and tried to build a pumpkin. What I don't understand is how you managed to let the shape go back in itself. When Revit creates a form (on my computer) it works its way up trom the lowest level, no matter what I try.


  2. Hi Wil
    Maybe start with a simple circle. Draw a circle in a mass family. Give the radius an instance parameter Load it into another mass family. Now it's a nested profile. Put 3 of these on 3 different levels. Select them all & make form. Now you have a cylinder. Make the top radius smaller. Now you can move the top level down until it is below the middle level. I will try to do a simple tutorial later.


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