3D digitising large objects

[Sweatshop]

Hi, I need to make some fabric covers for large structures (boats). The covers need to be as close-fitting as possible. Traditionally we used paper patterning to create a 3D model, 'unfolded the shape to create 2D patterns, digitised the paper patterns, exported into AlphaCam, created markers, exported into the cnc cut programme and then cut out the patterns on our 3m x 7m cutter. But this needs a controlled (indoor) environment for making the paper patterns and they can take up to 12 hours to make properly.
The boats can be up to 10m x 4m x 4m with all sorts of compound curves. I'm looking at the possibility of a laser scanner or Proliner 8. Any guidance guys?

[derekj308]

Hi sweatshop

Try these guys. They may have a UK partner.

http://www.3dscan-xpress.com.au/

Cheers

derekj308

[Sweatshop]

Thanks Derek. I checked the link but reckon I'll end up with a quality of data that's far greater than I really need and in addition I'll have a problem with setting up the controlled environment. We also make covers for aircraft and these can often be outside on airfields. There's also a potential issue with accessing the top of a tailfin (4m above ground) -which I could access on a stepladder but would have a problem trying to get to with the Atos scanner. So far the Proliner 8 seems to be the best bet but that's no doubt only my ignorance of the market.

[Jimasmith]

Hi Sweatshop,

I'm based in the UK and am an agent for Proliner. There's lots of info on their website www.prodim.nl

There are a number of Proliner devices available dependant on requirements and budget. Based on what you have said your best bet would be the Proliner 8-series.

This has a reach from the unit of 7m (ideal for your aircraft tailplanes), 8" colour touch screen, built-in CAD software, measures in 2D or 3D, stores files in a dxf format, mains/battery power and files are easily transferred by USB stick.

The key advantage of the Proliner is that set up time is merely the time it takes to start up the device. Just switch it on, create a file name, and start measuring straight away.

Prodim can also provide "Flattening Software". Fell free to contact me on jim@watersgroupltd.co.uk

All the best,

Jim Smith

[Sweatshop]

Thanks Jim, I'll contact you by email. I've looked some more at the Proliner website and you're right it looks like the tool for me

[LN-JET]

Maybe photogrammetry software, like http://www.photomodeler.com/index.htm could be used for your application?

Lars

[Sweatshop]

Hi Lars, I hadn't come across this programme before. Thanks for the suggestion -I'll con tact the company to find out what level of accuracy I can expect.

[svenakela]

One of my favourite URL's, maybe it could help you in some way.
http://www.rob.cs.tu-bs.de/news/david

[henry_phd]

3d scanning has different levels of complexity and processing requirements. That proliner is a good idea for a specialized market. You pull a pen connected to a string and it makes the 3d contour. I assume the string is attached to some sort of joystick device that gives the angles and the length of the string is also measured to give the x,y,z point from triangulation. Very neat concept but what a pain in the butt to have a tethered string for each point you want to measure?

You're worried about going up a step ladder? I'm imagining you will need a lot more than a step ladder to get at all the points with a tethered pen. You'd probably need a hydraulic boom crane with a man basket or other mobile ladder.

Also it collects 10 points a second from what I'm reading - not very detailed.

Other options are laser scanners as you might know.

Here are some tips:

1) Most laser scanners don't work well off reflective or transparent surfaces (windsheilds). The principle is very simple actually. A laser line is projected onto the surface. A camera takes the picture. Edge detection software picks up the line. The software looks at the distortion and calculates the distances based on triangulation.

You're going to have to coat the shiny metal parts and clear glass parts most likely.

2) Sounds like you need a CAD model so in additional to the laser scanner, you're going to need some expensive software like Geomagic or Rapidform. These both run about 20-30k US.

3) The learning curve is actually pretty steep for the above software.

4) If you're interested, we offer 3d scanning services of even big objects. We can fly out there, take the scans and give you the CAD drawing back for reasonable rates.

5) If you are doing a lot of scans and want to do them in house, we can even custom build a scanner (laser or string based like the proliner or even wireless pen) for you at comparable cost to the commerical products (in the 50-100k range).

6) If you decide to buy a commerical scanner, we can do the post processing for you. You give us the point data and we will give you back the CAD model using our engineers who are experts in 3d cad drawing and have access to software like Geomagic/Rapidform.

Send me a PM with your email and we can discuss some more.

Sounds like you're in a profitable market dealing with boats and airplanes.

[svenakela]

Because of another reason my workshop friend started to talk about photogrammetry later this evening, and as a surprise to me he had been working with it!
The idea is to project or create a grid on any surface (simple dots is working too), and the shoot a bunch of images from different angles. the images are then "morphed" together with help of the grid/markers and a 3D model can be created.
I think it can help me to solve a problem, and he said that 0.1 mm tolerance wouldn't be a problem with a standard digital pocket camera. As an example he said they added a tape grid on a sailing yacht (it doesn't even have to be straight, the line crosses are only there to tell a certain position that a bunch of images can be related to) to model the hull and the keel. They found out that the boat would perform better if the keel was 50 mm wider.

And hey, what's a post without a link: http://www.photogrammetry.com/

[cncuser1]

Why not just cover the object in a very cheap cloth that is way too big then just use saftey pins to contract the extra material? use that as a pattern for the good cloth.

[Sweatshop]

Hello Svenakela, Henry and User 1. Unfortunately the hangar guys don't like the idea of chalk dust on a $20m aircraft. I guess I can understand -and I know what you mean about the shiny surface error factor, I tried to get a scanner guy in for a boat but the scan had some very strange lines (because of the high polish on the hull). I'm still keen on the proliner but the talk about photogrammetry has stilled my cheque-writing hand until I find out a lot more.
The sheet and pins idea User1? Not so crazy, I've been using mylar and scalpels for 13 years.
Svenakela, if I tape the object (say just running a line of masking tape over the surface to create 1ft2 boxes over the whole object) -would this be good enough to use the photogrammetry method you speak of?