Unfolding Sheet metal for curved text/signs


#1

It’s my first post here so hi to all…
I work for a sign making company and I’ve been researching how to model 3d curved text then unfold the surface for a sheet metal cut file. Cutting the faces is the easy bit, it’s the returns that are proving tricky in other programs.

I’ve been hugely impressed by the model capabilities of Rhino. It can definitely handle making the geometry we need. But can it produce the accurate cut files we need without extra plugins? There’s bits and bobs around about unfolding surfaces, but how precise are they? and it is a quick process? What features do I need to research?There’s not a huge amount about this out there so any leads on tutorials or simple naming the features i need to research would be very helpful

I’m pushing to upgrade our cad software from coreldraw to rhino, but the speed, flexibility and accuracy of the unfolding is going to be the deciding point.
The models are fairly simple. Extrude text curved around a spline.something like these:



Many Thanks, Howard


#2

Yeah rhino can unfold something as that, i bought a few tutorials from infinite skills on rhino and from lynda.com and i have seen this a few times. I am also a nub but just wanted to say it is possible, i would also like to hear from the experts here.


(Margaret Becker) #3

There’s a simple tutorial in the User’s Guide about how to do this. Go to http://www.rhino3d.com/download/rhino/5.0/UsersGuide to download a copy.
One thing you have to be careful of is using the Rhino TextObject command to create you extrusion curves: TrueType fonts often make curves that have loops and gaps. The same advice applies to importing the curves from a drawing package. Just be sure to examine the curves carefully before making your extrusions. This process is accurate, but only you can determine if it works for you.


(Rajaa Issa) #4

Once you create the 3d geometry, UnrollSrf command in Rhino will help flatten the parts.
For added control over labeling/tabs, check PanelingTools, a Rhino lab plugin from McNeel (free). Here is a quick tutorial to show some of PanelignTools capabilities:


#5

Wonderful stuff! I’ve been doing some reading but wont be able to sink any time into the program untill this weekend.
Both unfold and smash commands seem like they’ve got what we need. Though I read unfold only works with one directional curves… meaning it wont work for curved characters going around a curve??! or is it just on about more severe curved shapes like spheres?!
I’ve got a short window of time to put together and good demo/examples, so any tips or leads however brief are always welcome… otherwise it’ll be solidworks; which I think is the wrong route given our requirements. And as someone who’s used 3ds max for many years rhino seems nice and in betweener of high level CAD + traditional modeling.


(Pascal Golay) #6

Hi Howard- UnrollSrf is made for ‘fully developable’ surfaces - ones you could make from paper, say, with no tearing or folding. Squish can help if the surfaces have some compound curvature; Smash is like UnrollSrf but it is more lenient about what it will try to unroll - the caveat is that non-developable surfaces will always unroll inaccurately, the amount ‘out’ depending on how much compound curvature there is. The surface area discrepancy is reported on the command line- you’ll need to decide if Smash output is good enough in any particular case.

-Pascal