David de Botton

Gents
Been wanting to build a detailed FB-111A for yrs & have all I need but no skill with producing acurate DXF or DWG files. The final drawing I hope to give to a contractor for laser cutting & ideally to get parts produced on a CNC milling machine. The drawing being the expense I cannot afford so "one day" I hope to reach that goal.

I would really like to produce "scale" drawings in AutoCad but it is too complex for me so I started using Auto Sketch for an introduction.

Problem I have is making the image I want to trace the correct scale for the Auto Sketch page ?

The image I scann into Photoshop & save as a large Bitmap file. Open this up in Auto Sketch and start tracing. I can stretch the image but this distorts the scale.

How to make the image the correct size size to then match the size of the page I set up ???

Cheers
David

BMatthews

You're putting the cart before the horse. Trace over what you have then move the image master away then scale up the vector stuff to the right size. Being 0 width the CAD lines scale wonderfully easily.

Bear in mind that you'll need to clean things up a bit. Tracing over any image is only approximate and how accurate it is is heavily based on how fine the details of the scanned image are. The coarser it is the more touch ups to the CAD work you need to do. Even if you scale up the image file the coarseness stays in scale. Blow it up enough and the edge lines get REALLY stepped and fuzzy. This is why the raster to vector conversions just never seem to work well.

Good luck with your project.

CoosBayLumber

My Feedback: (1)

Well, have done what you describe several times already. It can or can't be done in Autosketch, depending upon which version you are using.

Basically, open up a raw drawing, then import the Bitmap image at any scale ratio. Begin your vector tracing operation, and close out. You need not complete it all, but can do in steps. Only thing is once you have the image all lined up, don't mess with anything that will alter the position, scale ratio or rotation.

Next, open up a new blank drawing. Go through the MVIEW routine, and create a blank frame in Paperspace. Import the drawing you had been tracing in using the XREF command. Then, use the SCALE *.XP command to set up whatever model size you eventially want. This may be 1/5 or 1/6 or some other ratio. Exit the MVIEW port, and you then have a clear sheet all set for plotting at the size for the model you will eventially want.

Go back and open up the original drawing with the image file, and continure on with your tracing. Close it, and bounce back to the drawing with the MVIEW and see how your work is going. When using the XREF command, any changes you made in the image file will immediately be reflected upon opening up the MVIEW plan.

There is a difference here. As you measure the image and your vector linework, it will read in wahtever scale you created it in. If real size, then those numbers will be large. When you open up the MVIEW drawing, it will measue proportionately smaller, in the size you want the model to eventually be at.

When you eventially need to produce smaller (proportionate) sized lines, then just do the standard insert at the scale ratio used in the MVIEW, and work from there.


Wm.

David de Botton

Really apprecaite your effort to set me straight but I am one lost puppy when it comes to AutoCad & your terms of reference.

I have traced all details in Auto Sketch then selected all & pasted onto a new page & steched it all to the 6 inches I want the part to be using the grid as a reference mark before checking the actual measurement. When I got it to the measurement needed I then saved it as a AutoCad DXF or DWG file. Opened this up in AutoCad & then used the regenerate function & all appears with round edges where you want them to be.
This is all in the hope I can build the landing gear for a r / c jet model.
Will this project ever get off the ground ?
May have to do a course at the local colledge :-)

Cheers
David