CAD programs that don't suck

September 30, 2006 5:05 PM

Looking for a decent free CAD program that can import an existing blueprint in TIFF or JPG format.

I need to make some redline changes to the basic layout of an apartment I'm renting and have had a hell of a time trying to find something that will work for me. I need to be able to import the original drawing and then add new walls and appliances and stuff. Something that could take the scale from the original drawing would be ideal. Don't even really need a CAD program, could do it all in MSPaint if it had a free rotate function. Any ideas?

Oh yeah, something easy to use would rock.

posted by Jawn to Computers & Internet (9 answers total)

The problem is that TIFF and JPEG are image formats, whereas CAD programs expect to get data in a slightly more useful format.

Basically, your image is a large set of color values for the pixels in the image. There's no information there on whether or not a particular pixel is part of a wall, the floor, a notation, or whatever. The CAD program expects to get data that says, explicitly, that there is a wall from a point at (4', 4') to (4', 16').

You could write a PhD thesis on accurate conversion from an image to what the CAD program wants. (And people have; and I'm working on a related problem for mine.)

Since you said you'd be happy with a painting program, may I recommend Inkscape. It's a vector graphics program that will allow you to import raster images for use in your vector layout. You can then add your walls, appliances, etc. with the vector graphics, and export the entire thing as a new PNG (or whatever).
posted by Netzapper at 5:35 PM on September 30, 2006

What you have is a raster image. Most CAD documents are in a vector format. (The common dwg -- autocad or the dxf standard.) So you are going to have to convert it and then import it into a CAD program [AutoCAD, ProgeCAD, A9 Cad] if you want CAD functionality.

Something easy might be be google's sketchup program, I haven't played with it, but the route that I am suggesting above will take you loads of time to figure out and feel your way thru.
posted by bigmusic at 5:35 PM on September 30, 2006

Response by poster: To clarify a bit, I don't really need CAD functionality or 3D support or anything, I just need to add some walls and doors. Ideally I'd like to import the existing drawings as a background image and just draw on top. Having a CAD program that can auto measure the walls and has prebuilt door and toilet and sink symbols would be great, but it sounds like that might not be possible. I'm downloading inkscape now, will find out soon if that will work for me.
posted by Jawn at 5:44 PM on September 30, 2006

Inkscape will work fine for what you want, except for the measuring... I just drew my own floorplan with it, and I found it to be more than suitable for sketching.
posted by friezer at 8:21 PM on September 30, 2006

Canvas will do the job. It's pricy but they do have a free time limited trial however I'm not sure if you can save in the trial version.
posted by Mitheral at 8:53 PM on September 30, 2006

Sketchup (linked above) is designed for just this situation. Maybe there's a better way to do it, but when I want to "add walls" to my raster floorplans, I make a huge flat rectangle in Sketchup, set the texture to be the raster floorplan image, then start tracing over that image with rectangle walls.

It works beautifully and when you're done you get a snazzy looking 3D view, too (if you want).
posted by yellowbkpk at 9:22 PM on September 30, 2006

I am not the OP, but this software (Google Sketchup) is incidentally just what I need. Thank you for the pointer!
posted by Herr Fahrstuhl at 2:37 AM on October 1, 2006

Oh, and if you try Sketchup, be sure to enable OpenGL hardware acceleration in the preferences, otherwise the thing is pretty slow.
posted by Herr Fahrstuhl at 2:55 AM on October 1, 2006

Response by poster: Thanks all for the Sketchup reccomendation, seemslikethat'll dothetrick. Spacebar ain't working so well.
posted by Jawn at 8:20 PM on October 3, 2006