To manufacture a sculpture in PMMA, I’m trying to model a set of 8 mm thick panels that will later be glued together. However, I’m having trouble with the angles between the panels, as they are very complex: none of the panels meet at a 90° angle, and everything is skewed.
Getting planar panels is already challenging, but as soon as I add thickness, the geometry becomes completely messed up.
How would you model this object, and which specific tools or commands would you use?
It will be cut using a laser cutter, and the angles will then be refined manually on a table saw. No 5-axis machining is available.
At the moment, I’m using the Shell command and then modeling each panel face by face.
However, my main challenge is first obtaining completely planar surfaces without significantly altering the original model, which is proving quite difficult…
IPlane with 3Point option and select three points which define the plane you want. Create the infinite plane.
Turn on control points of the existing surface.
Select the control points.
Pull (if you want to move the surface normal to the infinite plane) or Project (if you want to move the surface in a particular direction to the infinite plane).
Select the infinite plane as the target surface.
_selPlanarSrf (for checking)
to make surfaces planar:
Gumball → orient to Object → z-Scale to 0
Scale all surfaces so they nicely intersect.
_createSolid to get a base-Volume
_extrudeSrf to get initial plates
_BooleanIntersect (baseVolume with plates)
_BooleanDifference (to solve edges)
above workflow can be easily scripted if you have many of those plates.
for 2d - lazy workflow:
sub-Select the Surfaces (not the entire polysurface)
_unrollSrf
to get it into 2d
do you have a nice modern table-saw with “cycle programs” (Zyklus Programme in German) (which set the stops and adjust the saw blade angle) ?
I implemented a process on a Martin T75 for a customer and it turned out very nice. - but there is a few tricks to get it reliable…
laser-cut the initial panels - with a standard 2 or 3 mm wider / with addition.
That’s the kind of circular saw a company used, when they built a prototype 2m x 1,5 m for us for an exhibition, only way to cope with so many different angles. Only one attempt, and everything fitted like hand in glove. I was pretty well chuffed.
I would use OffsetSrf with Solid=Yes rather than Shell. Shell is essentially a combination of removing one or more surfaces from a polysurface and then OfffsetSrf with Solid=Yes.
The challenge can be laying out the joints. First you need to decide on the design direction. Will the joints be miters or butts? That fundamentally changes the approach.
What is your experience with designing the construction of objects which will be built?
I’m used to working with the company that manufactures my sculptures, but my previous projects were generally simpler and involved more right angles.
It seems to me that the advantage of OffsetSrf is that it makes it easier to visualize the resulting edge conditions and possible joint angles (see screenshot), compared to Shell.
The final piece will use a mix of miter joints (where three panels meet without a right angle) and square/butt joints (where only two panels meet).
@laurent I couldn’t find Voronoi Cell, but unfortunately I’m not very familiar with Grasshopper
