topic Re: Scan timber samples to create Autocad drawing in AutoCAD Forum

Scan timber samples to create Autocad drawing

rmeyers — Mon, 13 Jun 2022 22:45:57 GMT

We are a company that makes timber moulding and often have people bring samples from old house they want to match. Currently we tediously measure and guess and repeat until we get it right. They can take hours and hours. We only need the end profile of a moulding, is there for us to cut a slither off the end and scan it into Autocad to create a drawing? Even if we have to trace the drawing once it is in there? Thank you

Re: Scan timber samples to create Autocad drawing

jotaferrer — Tue, 14 Jun 2022 11:09:20 GMT

Hello, you kinda figured it out, in my opinion. If I had to it, I would:

- Cut a slither off the end;

- Scan it;

- Import it to AutoCAD;

- Scale that image properly;

- And then redraw it.

It's totally doable, sir! If you need further help, I can give a hand

Re: Scan timber samples to create Autocad drawing

rmeyers — Wed, 15 Jun 2022 00:37:40 GMT

Can you use a normal scanner or does it have to be a special type?

Re: Scan timber samples to create Autocad drawing

rmeyers — Wed, 15 Jun 2022 03:05:54 GMT

Thank you for your help. I am practicing with a drawing and when imported the dimensions are only slightly out but when I scale the drawing using two reference points to get the dimensions I need, the dimensions in the other direction are not correct. If I fix that dimension it changes the one that was correct and is now not correct if that makes sense. Are you able to assist?

Re: Scan timber samples to create Autocad drawing

leeminardi — Wed, 15 Jun 2022 11:23:42 GMT

Your scanner has some nonlineariries. Try the following to calibrate the distortion.

Scan a piece of graph paper that has a uniform grid of known grid size.
Insert the image into an AutoCAD drawing and scale it so that the horizontal dimension is true. When using the dist command for measurements use points as far apart as possible for the best precision.
Measure a vertical distance between two points that are the same number of grid untis apart as the two points used for the horizontal distance.
The ratio of the horizontal to vertical distance is the aspect ratio of distortion for the scanner.
When you trace the outline of the molding in AutoCAD use only lines or polylines without arcs. If the molding has arc segements then create an arc and then convert it to lines with sufficient precision.
Create a block from the tracing and then insert the block but use the aspect ratio for setting the scale in y different from the scale in x.
Print the results and compare it to the physical molding.

The distortion your scanner has is probably not uniform throughout the entire scanning area. More sophisticated techniques would allow you to use multiple points in a scanned image to compensate for the scanning erros. Google maps uses such techniques to patch together multiple scanned photos to make a composite image.

Re: Scan timber samples to create Autocad drawing

jotaferrer — Wed, 15 Jun 2022 16:00:04 GMT

I'm here to help! It can be done in a normal scanner, but it should be calibrated. You can do as @leeminardi posted. If you need further help, please post here!

Re: Scan timber samples to create Autocad drawing

dany_rochefort — Wed, 15 Jun 2022 18:53:11 GMT

Use the photocopy machine to scan...

Cut your slither

Put your slither photocopy machine

Put 1 ruler on photocopy right next to your slither

Scan to PDF, highest resolution possible

Import into cad and ''scale reference'' using the biggest measure on your ruler available, either 12'' or 300mm

Put pdf on defpoint layer, lock it and trace over it using another layer

Draw a reference line next to it, 250mm for example and print your drawing to scale

Take your piece of paper, measure your reference line to make sure it really measures 250mm ''on paper'' to confirm your drawing is really ''to scale''

Once confirmed, cut it out using scissors and compare that to your slither sample

Make adjustments to cad drawing if required, 2 or 3 tries should get you there

For this to work, you need to be able to print to scale everytime.