Edit 3D Parts Like a Sketch

How do you edit a sketch? It’s easy, right? Make sure it’s locked down somewhere, has the relations and dimensions it needs to change the way you want it to, right? Changes can be made by changing dimensions, changing relationships, adding or removing elements. It takes a little getting used to when you start, but it works, and a lot of CAD systems have worked this way for decades.

You can drag sketch elements with the cursor, or change their position or size with dimensions. You can relate sketch elements to one another or with other geometry in the part so that they move together in predictable and controllable ways.

And the old adage is definitely true – create once, edit 10 times. Your CAD tool is only as efficient as your ability to make edits.

The point is that working with sketches is relatively easy and becomes intuitive with a little practice. You know that straight lines can be extended infinitely, arcs can be extended until they self-intersect, splines can be extended, but because of the math, they don’t work like other sketch elements.

What if – what if you could work with 3D geometry the same way you work with 2D geometry? Move faces, change dimensions, add relationships… That would simplify things, wouldn’t it? How many times have you made an edit in your history-based software, and it blows up something in the tree, or you get back something you didn’t expect? Then you have to go back and play detective to find out what went wrong and fix it.

Or, how many times have you imported parts, and then had to use hack-and-whack modeling to chisel out or bondo on edits? Very inelegant.

Even on your history-based model, you sometimes just double click a face of the feature you want to edit and change the dimensions directly, right? Sometimes you by-pass the sketch and just work with the actual 3D geometry.

And what if you could decide which direction changes move things at the time of the change?

All of this is possible. The days of setting up sketches and feature order to get the right edit function are over. Just work with the finished 3D geometry, and don’t mess with sketches, feature order, parent/child dependencies, rebuilds or repairing errors. In the above animation, the 0.625 dimension can change to either side, or symmetrically just by scrolling the wheel on the mouse.

I’m not a salesman, I just like this stuff, although I did have a free license for a period of time for a project.

Red dimensions can only be changed directly by the user. Blue dimensions can be changed by the user or by the interface tools such as steering wheel, or by other changes. You can add relations to the faces, so I have 3 faces grounded. The Design Intent window controls automatic relations applied by the software, but you can turn them on or off as you need. So in the above animation, I turn off concentricity and aligned centers to get the hole to move off the center of the tab.

A lot of these changes you see look like they are just visual changes, but they are or can be real dimensional changes with all the precision you need in real design. This isn’t just “squint one eye” kind of changes.