Lock aspect ratio

[labmonkey]

Hello all,

 

Hopefully this is a simple question to solve, which will make me seem a little stupid, however, I was not able to find the solution from searching this forum and google.

 

I have imported an image into AutoCAD 2007 education version. The aspect ratio is a little wrong, so I would like to stretch it in one dimension. In another version of AutoCAD (LT 2008 ) I can simply right click on the picture to open the properties where there is an option to lock/unlock the aspect ratio. However, in this version there is no such option in the properties. It appears that by default the aspect ratio is locked, i.e. any stretch in the x direction is simultaneoulsy copied in the y direction.

 

Does anybody know how to unlock the aspect ratio in this case? Is it because of the version I am using? Is it in another menu instead of properties? Is there a keyboard command to unlock aspect ratio?

 

To complicate matters a bit further, this is the Japanese version, however, I am fairly sure that is not the cause of the problem.

 

Many, many thanks,

 

Giles

[GE13579]

You're studying in Japan? I don't know how that would work with a western keyboard regarding what keys do what?

 

I'm afraid I don't work with images at all but could you modify it in a picture editor before you import it?

[labmonkey]

You're studying in Japan? I don't know how that would work with a western keyboard regarding what keys do what?

 

I'm afraid I don't work with images at all but could you modify it in a picture editor before you import it?

Thanks for the reply.

 

The image can be resized in a picture editor before importing, but it's much, much simpler to do it all in AutoCAD. Particularly as it needs to be done precisely, so you'd have to import twice, the first to work out the exact resizing needed, and secondly once the resizing has been done.

 

It's not that difficult using the Japanese version. I tend to use a UK keyboard, but a Japanese keyboard isn't so different (it's QWERTY with the Japanese characters created using an "alt" version of the same keys). It's sometimes a bit tricky to find things in menus, but you can often guess from the icons.

[Bobzy20]

Did anybody resolve this problem as I would also like to unlock the aspect ratio of an image I just imported into AutoCAD 2012?

[SWfangirl]

This might help.

 

Bill Fane provided us a with a way to insert raster image files whose aspect ratios are out of sync.

"Problem: You want to insert a raster image into a drawing, perhaps to trace over it with AutoCAD lines, circles, arcs, etc., but the aspect (width to height) ratio of the raster image isn't correct. Unfortunately, although inserting a raster image seems to be almost identical to inserting a block, you can't specify different x and y scale factors.

 

"Solution: Insert the image at the default 1:1 ratio, and then create a block that includes the image as a component of the block. Now insert the block with different x and y scale factors. Bingo! The image stretches appropriately.

 

Do you have standard cad or map?

[Bobzy20]

Thanks for that. I tried this but don't really understand how to do it.

I'm just using normal CAD.

[SWfangirl]

Once you turn the image into a block you should be able to right click on it and in the properties box change the x,y scale. Or when you insert it you should be able to change the x,y,z values in the insert dialog box.

[CyberAngel]

1) insert the image in the normal way.

2) create a block with the image as its only member (may need to toggle image frame with TFRAMES). You may want to put a corner of the image at 0,0, or use some central point, depending on how you'll do your scaling.

3) adjust the block's X and Y scale factors as needed. I like to start with a baseline scale, e.g. 1000, measure a known distance, and work from there.

[SWfangirl]

:oops:Thanks CyberAngel I kinda skipped the block creation part. My mind seems to work faster than my fingers sometimes.

[Bobzy20]

Once you turn the image into a block you should be able to right click on it and in the properties box change the x,y scale. Or when you insert it you should be able to change the x,y,z values in the insert dialog box.

 

This doesn't appear to work as once you create a block you don't have the height & width properties.

[Bobzy20]

1) insert the image in the normal way.

2) create a block with the image as its only member (may need to toggle image frame with TFRAMES). You may want to put a corner of the image at 0,0, or use some central point, depending on how you'll do your scaling.

3) adjust the block's X and Y scale factors as needed. I like to start with a baseline scale, e.g. 1000, measure a known distance, and work from there.

 

This way works although if you measure the image with the distance tool it doesn't match the scale dimensions. Maybe because I am using the scale factor to resize the image and not the normal width & height measurements.

[CyberAngel]

This way works although if you measure the image with the distance tool it doesn't match the scale dimensions. Maybe because I am using the scale factor to resize the image and not the normal width & height measurements.

 

Not sure what you mean by that. When AutoCAD gets an inserted image, it doesn't automatically know how to scale it. If the image contains a graphic scale bar, for instance, you can look at it and know what it means, but AutoCAD can't. Images don't have an inherent coordinate system, so you have to match them manually as best you can to the coordinates in your drawing.

 

It just occurred to me that you could use the Align command to scale an image with a graphic scale. All this time I've been doing it manually....

[Bobzy20]

Not sure what you mean by that. When AutoCAD gets an inserted image, it doesn't automatically know how to scale it. If the image contains a graphic scale bar, for instance, you can look at it and know what it means, but AutoCAD can't. Images don't have an inherent coordinate system, so you have to match them manually as best you can to the coordinates in your drawing.

 

It just occurred to me that you could use the Align command to scale an image with a graphic scale. All this time I've been doing it manually....

 

I'm going to try Photoshop and see what I get.

 

If I import my raster image in the usual way and right click and change the width to 10560mm and then measure it using the distance tool it measures 10560mm.

 

If I insert the image and the block it, right click and change the X scale factor to 15060mm and then measure it again using the distance tool it measures 9738423.5000mm.

 

Also the Align command didn't work for me.

[JD Mather]

]If I insert the image and the block it, right click and change the X scale factor to 15060mm and then measure it again using the distance tool it measures 9738423.5000mm.

 

Entering a scale is not the same a saying - make it this length.

You need to calculate the correct x and y scales.

 

Draw line of known feature length next to x feature. call this "a"

Draw line length of the image x feature. call this "b"

sf= scale factor

b*sf=a

sf=a/b

Repeat in y direction.

 

Now insert the image block with your sfx and sfy

 

attach your image file here if you can't figure it out.

Edited November 2, 2011 by JD Mather

[Bobzy20]

L=15060mm

W= 9728mm

[Bobzy20]

Sorry i cant post the image now for some strange reason.

[Bobzy20]

Here you go.

1.zip

[JD Mather]

I woke up in the middle of the night and realized I had the a and b backwards above. (should be correct now)

I will verify the true calculation in a couple of hours when I really wake up.

[JD Mather]

sfx=23.28956

sfy=23.54862

[Bobzy20]

Thanks it worked lovely. I have 5 more to do now with different sizes and the images are different sizes as well. I just tried one following your directions and it came out completely wrong.