What is the current best method of sheet metal and plastic bending?

having to work out the shape of metal and plastic bends then construct the solid to match reality is a pain.
Doing a twist in metal even worse, has Rhino a better way now ?

How does one for example bend a 100 x 50 mm 2mm thick sheet of metal or plastic such as that object in my post on smash etc. I did it by drawing the radiused curve and solid extrude etc.

Test accuracy smash v unrollSrf unbending sheet metal.3dm (304.6 KB)



This thread appears to be a variation of What command to turn a simple L bend in e.g. 2mm sheet to a plan of the unbent sheet?

Bending plans into the final shape or having to create an item that I am looking at that is already bent, uses a completely different command set to trying to flatten back out though. best keep both as different threads else responses are going to get muddled with some going in one direction and others in the other.

folk searching on bending wish to see a thread focused on such, not unbending.


Asking again as looking at past asks/threads I see dead ends on all.
Please what do I need to plug into Rhino or use in grasshopper or purchase elsewhere to add useful additional commands, to do the occasional sheet bending, taking a sheet and bending it, NOT CONSTRUCTING IT.
There are times I cannot tell what the bent item is going to be like, and this ask is for such times. There are progs like inventor that are full blown CAD progs that you buy when first deciding what CAD route you are about to take, that cost A LOT OF MONEY and will be that big purchase you make to do the CAD work you need. I dont want to be buying such for the occasional sheet bend, I simply dont have the funds to get 2 main CAD progs, having been told Rhino can do my aircraft fabrication., primary aim to get V6, and air con (£4k) as 31deg C afternoon and evening till midnight in the UK is not good for a work environment.

Two you tube videos look great, but folk asking how to get hold of it are met with silence.
https://www.youtube.com/watch?v=qbtK5vVbkjo I cannot find a way of buying or downloading what he/she has there.
https://www.youtube.com/watch?v=YBaEj_JF5Yg&t=23s again dead end looking at replies.
DesignSpark the free Spaceclaim is nuked.
Spaceclaim killed by lack of proper forum.
I see https://www.youtube.com/watch?list=PLONdQc9bizscSCvQuoFVFVClVSTLve0wT&time_continue=26&v=jaPScAM1W_w&feature=emb_logo but havent established forum data or price yet.

What else is there, or has someone got an affordable easy fix to such a VITAL requirement.
If it also does unbending back to 2D plan then I can kill two birds with one stone.


Rhino has no native “sheet metal” bending tools.
I’m not aware of any plug-ins either.
Typically, sheet-metal bending tools are add-ons to parametric, feature solid modelers.

Rhino is a non-parametric, industrial design, surface modeler.

Rhino doens’t have parametric sheetmetal, that’s a very specialized thing. Even if your CAD HAD it…well are YOU making these parts or are you having them made? 'Cause the way workflow works in Rhino is to just model what you want the result to be and then the parts supplier will model it up in Inventor or something with all their own k-factors(which can vary from machine to machine) and the right corner details and make you the parts–which they may do regardless of your CAD. If you want a general idea of what the flat sheet will be like for quoting, model the parts as a single thin polysurface, usually along the middle of the sheet thickness, which is easy to flatten.

1 Like


seems like it might be a solution ?

I currently am reverse engineering a bracket for someone building an aircraft, measured the wrecked item, drawn it in 3D, but one part I need to fold a trace of the surface I have managed to make, to see where the arch goes,

supply 2D plans made from the 3D then he will take vice and hammer and 0.03" sheet steel and make it.

I also have had 2D plans of a/c parts and had to bend them to shape to place the 3D object into my 3D assembly area as I built my 3D aircraft. to then generate wood formers to replicate it as a skinned static.


You have got to be kidding. Why bother producing a CAD file at all if this is your manufacturing method?


Possible these notes will help?SheetBends [Converted].pdf (5.7 MB)

Mristau, thanks I will study that and try sheet folding that way.
…update…it works a treat :slight_smile:Gijs on another thread of mine has suggested same method with copy yes and stretch no and history on so that editing line afterwards sees fold change.
Copy pasting the object and its lines and sheet breaks history, need to export it instead.

Mark Leichliter.
I am open to other ideas so please say what you would do that is better than what I was asked to do.
Please explain the workflow you would use when someone asks you to take an item they have unbent as best they can from twisted wreckage, asking that they receive plans they can lay on sheet metal to cut out and bend and weld into the original item., for which no original plans exist.
By modelling in CAD as 3D I can see I have the various parts all working and matching up, I then simply smash etc and provide 2D plans to him as requested by him.


I want to unsee this, because it’s too awesome and it’s not in Rhino. :crazy_face:


I spoke to BricsCAD, very expensive as need the pro package then the sheet metal addon.
at least cost of rhino and more.
Perhaps they might consider stripping out all tools except bending and market such to assist Rhino and Autocad users neither of which have a bend sheet function or unfold, I suggested !


The fact that they sell this functionality only for the “Pro” package means that they are perfectly aware how valuable the sheet bending component is, so they would never offer it as a plug-in for their competitor CAD programs. The same goes for the 5-axis functionality of the leading CAM software, which is locked behind expensive upgrades. :slight_smile:


Take a look at Fusion360 sheet metal:

And the price is very affordable. Especially with theirs current 50% off:

I think they even have a free version for startups and companies making less that certain revenue.



They changed this at the end of last year, now it’s only start-ups with the following requirements that can have access to this free version.

Fusion 360 for startups is eligible for venture-backed, angel-backed, or bootstrap startups that are less than 3 years old and have 10 or fewer employees.

Businesses must generate less than $100,000 USD in gross annual revenue (including parent entities) and have a valid website or transact on a social media or digital platform.

Businesses must design or manufacture their own physical products and be willing to share their story with the Fusion 360 community.

Service providers, resellers, contract manufacturers, and consultants doing work for other companies do not qualify for Fusion 360 for startups.

This is a classic garbage in, garbage out scenario. In a case as low-tech as this, I would just hand-build paper patterns from the wreckage to arrive at something that is just as accurate (read: inaccurate) as a guessed-at CAD solution. Furthermore, with the implication that this is going to be part of a craft intended to be airworthy, the lack of rigor in your design approach AND manufacturing scheme makes me grateful for safety inspections. If a client presents you with an impossible task exacerbated by questionable safety standards, it is always acceptable to JUST SAY NO.


adding that Jodyc111 also suggests Fusion360. Pity its no longer free.

In response to a pleasant reply…ouch :frowning:

I have not produced garbage ! You have no idea of what I have created, how accurate it is, have accused me of producing something unfit for a flyer.

arrive at something that is just as accurate (read: inaccurate) as a guessed-at CAD solution.

I DO NOT HAVE A guessed at CAD solution. I now have an ACCURATE replication of the item, it is for what used to be a flyer, and in fact what I have here would match the original plans. When I reverse engineer something I know what I am doing AND I AM EXTREMELY ACCURATE in my work. I specialise in such things.

with the implication that this is going to be part of a craft intended to be airworthy, the lack of rigor in your design approach AND manufacturing scheme makes me grateful for safety inspections.

I never implied such for one moment. Ask before you assume. It is not going into a flyer, I never said it was going to. I know what is required for such and for starters one needs to be an approved aircraft engineer.

lack of rigor in your design approach

How dare you say that, I have poured over this with vernier gauge, measuring three times, doing traces with my special methods.
You dont know what methods I employ and yet say that, insulted !

I can assure you though that such engineers would study my plans and the wreckage, and stamp it approved ! You also refer to the static aircraft restorer, I could mention this to him but the response would be edited out by the admin I AM SURE ! He knows exactly what he is doing and the replication with vice and wood and sheet steel for this particular part is standard practice. You havent even seen it yet say that.

Too many assumptions.

If a client presents you with an impossible task exacerbated by questionable safety standards, it is always acceptable to JUST SAY NO.

Who said it was impossible, I didnt… If its impossible yes say no, anyone would !
If safety standards applied to it and it was doubtful the wreckage could yield original accurate shape, again say no. quite right, I would be the first to do so, but none of that applied.

Its a non structural component for a static restoration of what used to be a flyer, but wont ever again fly., made in the manner I described so remaking it that way is perfectly acceptable. its 80 yrs old. Practices carried out by the warbird fraternity to remake parts.
Time spent in reconnaissance is never wasted. No flaming please as I have never flamed you. I am a friendly guy and have never ever received a reply such as this and had to write a response until now as such.

I am an expert in reverse engineering, whilst still learning Rhino which I did ask is it suitable for aircraft parts CADing and was told yes, then I find it cant do metal bending. It gets me through on the reverse engineering and replica restoration scene, .


Review this please.

You’ve misinterpreted my intent. I was genuinely offering some perspective, and trying to help. Didn’t mean to offend - at all. The “garbage” reference was just to try to help you see that going from a bent, distorted piece of metal, to CAD data, to a hand-built approach to manufacturing your client’s part was unrealistic and unnecessarily complicated. I’ll leave you to it - and wish you luck on the project!

Forum response to a private message
I don’t know what is going on in your life and it’s not my concern. You need to take a deep breath , re-read the FAQs. Pose your forum questions succinctly and you will surely get the desired responses from helpful members.

Don’t bother sending me private ranting messages; anymore and I will post it to the forum.

Best regards