Polyhedron Model-Making Tips
Pictured above are the tools I use for constructing my polyhedra:
- A metal ruler and large doll-making needles for scoring
edges.
- Scissors and glue for obvious reasons.
- An old piece of card for putting a blob of glue on. It's almost solid
glue now!
- Wooden skewers for applying the glue. Possibly not the best
thing, but they were the first thing I found and they worked, so I'm still
using them. They don't require much cleaning like brushes, and stray
bristles don't cause problems either.
- Tweezers, including a long pair with angled tip, for squishing
those tabs together.
- The top cut off a coat hanger, for those hard to reach tabs
(I practically never need this though).
- I also have some wooden clothes pegs, taken apart and put
together backwards as recommended by Magnus Wenninger, for clamping tabs as
they glue (but again, I almost never use these).
- And finally of course, a Buffy pencil case to put these tools
in!
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A box with compartments can be very useful too when working on a model
with many different parts.
Here the box contains all the parts required for the
pseudo great rhombicuboctahedron.
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To make models, you'll need to start with nets. You can print these out
from
Stella4D,
Great Stella
or
Small Stella.
Score along the edges, cut out the nets leaving tabs around the outside, crease
along all the edges, then glue the pieces together (tab to tab).
Here are a few general tips for building models.
- I use quite thin paper, although it is thicker than normal typing
paper. The paper I use is mostly 120 gsm. I find Canson's Vivaldi
paper to be very good, and it comes in a wide range of colours.
Thinner paper leads to a more accurate model.
- Be careful to score on the front of the paper for a convex fold
(mountain fold), or on the back for a concave fold (valley fold). Make
tiny pin-pricks at each end of lines to be scored on the back, so you
know where to score. The program has the option to use dashed line
when printing concave edges, but I prefer not to see them in the
finished model. If in doubt about which ones are which, print a page
with dashed lines on normal paper as a reference.
- I use double tabs. This means that I usually leave tabs on all
edges around a net, and glue the tabs to each other where faces meet.
This makes the edges more "symmetrical", since both sides have a tab,
and it is easier to squish the tabs together with a pair of tweezers.
- Where faces attach very sharply (a small dihedral angle), I often use a
single tab, and glue it under the joining face. Otherwise the
final edge becomes too "bulky".
- I usually try to use some kind of internal support to give the model
rigidity. I hate "floppy" polyhedra (eg see the
great hexacronic icositetrahedron).
Stella has a number of features to
help with this, including a mode for creating new polygons inside the
model using existing vertices, which you can print out and glue inside
for support. A lot of people use thicker card than me and don't seem
to worry about this though.
- When gluing a part behind a surface that will be visible (eg when
using single tabs, or for extra support, eg see the
great dodecahedron), don't put the glue
behind the visible surface. Instead put it on the surface being glued
to it. This is because sometimes the moisture in the glue can cause
wrinkling, and it's better to avoid any wrinkles in the visible
surfaces. Also, don't put glue all over largish areas, just near their
edges, to avoid further wrinkling.
Copyright © 2001-2009,
Robert Webb.
