How to Combine SketchUp’s Scale and Follow Me to Make Organic Forms
One way to create extruded forms in SketchUp is to use Follow Me. This technique is ideally suited to making long, curvy, tapered things like tentacles and antlers; it’s a little time-consuming but works like a charm.
Modeling a simplified bull’s horn is a good, straightforward illustration of how the Follow Me variation of this method works. Here’s how to go about it:
Draw a circle.
This is the extrusion profile for Follow Me. Strongly consider reducing the number of sides in your circle from the standard 24 to something more like 10 or 12.
Draw a 10-sided arc that starts perpendicular to the center of the circle you drew in Step 1.
Type 10s and press Enter right after you click to finish drawing your arc.
This tells SketchUp to make sure your arc has 10 sides (instead of the default 12). Why 10 sides? It makes the math easier a few steps from now.
The easiest way to create a halfway-accurate arc in 3D space is to start by drawing a rectangle. When you’re sure this rectangle is properly situated, use the Arc tool to draw on top of it and then delete everything but the arc.
Select the arc you just drew.
This is the extrusion path for Follow Me.
Activate the Follow Me tool by choosing Tools→Follow Me from the menu bar.
Click the circle you drew in Step 1 to extrude it along the path you drew in Step 2.
Choose View→Hidden Geometry from the menu bar.
Showing the hidden geometry in your model lets you select the edges that were automatically smoothed (made hidden) when you used Follow Me in Step 4.
Scale the face at the end of your new extrusion by a factor of 0.1.
Use any of the four corner grips on the scaling box, and don’t forget to hold down the Ctrl key (Option on a Mac) while you’re scaling — this forces SketchUp to scale about the center of the face you’re resizing.
Select the edges that define the next-to-last profile in your extruded form.
Depending on the angle of your arc, making this selection can get tricky. Here are some considerations that may help:
Choose View→Face Style→X-Ray or View→Edge Style→Back Edges from the menu bar to make it easier to see what you’ve selected.
Hold down the Ctrl key (Option on a Mac) while you orbit to turn off SketchUp’s “blue is up/down gravity bias.” While orbiting this way, try drawing lots of tight, little circles with your mouse to get your view to tilt in the direction your want.
This is by no means simple stuff, but getting the hang of temporarily disabling the Orbit tool’s tendency to keep the blue axis straight up and down is a very nifty way to work. Doing so makes it infinitely easier to get just the right angle for making a window selection.
This in turn makes selecting the edges that define profiles a whole lot easier, and that’s what becoming a Zen master of the Orbit tool is all about.
Scale the edges you selected in the preceding step by a factor of 0.2.
Starting to see what’s happening?
Repeat Steps 8 and 9 for each of the remaining profiles in your form, increasing the scaling factor by 0.1 each time.
Of course, you can absolutely choose to sculpt your form however you like, but this method (counting up by tenths) yields a smooth taper.
Have a look at the Santa-Claus-and-reindeer project in the color insert (in the center of this book) to get an idea of the kind of fancy, not-a-box models you can build after you master the Scale tool. It’s not beginner-level material, but it’s worth the time when you’re ready.