Image import problems

[dbaldacchino]

Hi all,

I am importing some scanned images and for some odd reason, they are coming in at double the actual image size. So, for instance, a 2' x 3' scanned image comes in as 4' x 6'. These are 150dpi jpegs and I cannot figure out why this is happening.

[BillyGrey]

If a 2'x3' image misbehaved for me, I'd just draw a 3' long line, grab one corner of the image,
move that corner to the end point of the line, then grab the "handle" on the other side of the image and pull it till it snaps to opposite end of the 3' line. If the image did not scale proportionally, I'd run another line up 2' and snap the other corner to it to regain proportions.

It's a hack, but I hope it helps.

[dbaldacchino]

Thanks for the tip.

I know that you can scale an image, and in most cases this is necessary. But I was trying to figure out if there was some setting or not. I'm beginning to think that it has something to do with the image resolution. I think it uses 72 dpi as it's base and then scales from there. I'm gonna run some tests and will post the results.

[beegee]

>>I think it uses 72 dpi as it's base and then scales from there. >>
That's correct.

[sbrown]

what scale is your view? Is it the same scale as the scan.

[dbaldacchino]

The view scale didn't have any effect...it still scaled the scan double it's intended size (in other words, double what the view scale was...if the view scale was 1/8" and I inserted an image that was drawn at 1/8" and scanned 1:1, it would end up being twice it's intended size, 1/4" in this case). When I inserted a 72dpi image, it worked in any view scale....the 1/8" scan in a 1/8" view came in as 1/8". So I guess the "mystery" is solved :) Always use a 72dpi image to eliminate any confusion...or just scale the image manually.

I prefer the former approach for speed's sake and to minimize errors.

[Solomon]

I've found a simple and accurate way to scale imported images is to manage the scale from the image's properties (select the image, then right-click -> properties.) There's Width and Height there, as well as a check box for "Maintain aspect ratio." You could easily then put 3' in the Width box and it will scale accordingly (make sure "Maintain aspect ratio is checked".)

This is also an opportunity to be especially accurate: Since I rarely receive a scan that is exactly 36", I can put in the image's actual dimensions 35.96" and then be just that more accurate with the imported image....

Now if you could only rotate it...

Cheers,

Solomon

[dbaldacchino]

You're right. The 3' was just an example, and not everyone can check the exact dimensions of an image (or not everyone knows how!). That's why I wanted to figure out how an image can be imported at it's correct, dimensional size.

The rotation thing is irritating. You cannot rotate an image by, say, 6 degrees. And the rotate command looks like it's going to work, but nothing happens. You have to use the Flip/Rotate button.

I would like to have the same control that Autocad/ADT has over images ie: full rotation controls, being able to accurately snap to a corner to move the image (you can't do that in Revit either), brightness/contrast controls, transparency and cropping capabilities so you can align two images (like two floors) on top of each other.