Wednesday, October 24, 2012

Invent Intro #05 - Circles (Revolve Boss & Cut)

Like the EXTRUDE commands, REVOLVE comes in two flavors, BOSS and CUT.


Basically, REVOLVE uses a 2D sketch that is evenly swung around an axis to perform its job.  As the sketch is swung around it either ADDS or REMOVES material in its own shape.  REVOLVE (Boss) adds material along the path and REVOLVE (Cut) removes material along the path, if any exists.

The REVOLVE commands are relatively easy to use and are often the first thing users try when learning a new 3D CAD program.


There are two elements that must be selected for REVOLVE (Boss) to work.  The first, of course, is a 2D sketch.  The second is an axis around which that sketch will revolve.  The 2D sketch may or may not touch the axis.  But, it can never cross over the axis in Cubify Invent.

In general, sketches to be REVOLVED are either objects floating in space to either side of the axis or they are outlines of one half of a cross-section of the intended result.  It is very useful to design things like cups, wine glasses, bells or anything having a cylindrical construction.  In our sample we form solid walls with circles floating in space.


REVOLVE (Cut) also requires the selection of two elements, the sketch to be revolved and the axis around which the sketch will revolve.  But, instead of adding material in its wake, the sketch removes material from anything it its path in the exact shape of the sketch.  It's like having a custom designed bit for a lathe.  Therefore, it's great to use for legs, ornate columns or contours around an object.

Here is a video showing some experimentation with Cubify Invent's REVOLVE using circle sketches.

I hope that the video tutorial has been very useful in showing just how powerful both flavors of REVOLVE can be.


  1. Recently you wrote about bugs and features. I think I have discovered a bug. When creating a copy of a sketch, mirror, pattern and project have mechanisms to preserve the association with the parent sketch, i.e. the parametric. "Project" works great across parallel planes, but when projecting to an oblique plane, at 30 degrees for example, the result is a true projection rather than a copy. Circle becomes elliptical for instance. The "copy" command followed by "paste" or "stamp" will transfer the figure to the oblique plane but has no way to preserve the parent relationship even when the dimensions are copied.
    I was working on a parametric model of a circus big top when the issue came up. The tent round top has a undulating profile due to location of quarter poles at 12.5, 45, 57.5 and 90 degrees all related to the 0 plane. Makes for a nice loft, but cannot generalize for the different sized tops, Ringling, Cole Bros, Carson & Barnes etc.
    Damon Swanson

  2. This kind of comment is what makes blogging a true two-way street!

    You comment is fascinating. And, it's going to guide me in some new explorations. But, more importantly, I would love to see your designs.

    Keeping the parent relationship is relatively important if we are to trade .FUN files with the idea that recipients can make minor modifications that propagate to child features. Nice find.