Autocad Image Unlock Aspect Ratio
Rode Neagle
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?
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.
"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.
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.
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.
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.
Can image size/aspect ratio not be controlled when placing an image into a drawing sketch symbol? When creating a part and inserting an image into a sketch you are able to constrain/dimension the image. However, when placing an image into a drawing sketch symbol you are unable to constrain/dimension images and the only control of aspect ratio you have is when you draw the initial insert box which cannot really be defined either.
This looks like an intended behavior. It tries to limit the control to the image since the symbol should be relatively simple and straight forward. But, one can argue that it can be used just like AutoCAD Blocks. And, sketch geometry can be dimensioned and constrained in general. This is inconsistent.
Thank you, I hope there can be a fix for this, the specific use case that I have is a "stamp" that gets placed on drawings. It has a well known logo on it and per the companies policy the logo has to maintain the exact aspect ratio that it was given to us in.
Hi! I check with the project team. We could not find a definite reason. It could be related to the fact that a symbol can be scaled, so the absolute dimensions may not be relevant. However, one can argue drawing view can be scaled and the measurement still holds true.
@johnsonshiueThis really isn't a solution since you cant constrain the image to the rectangle in anyway. The problem is by not being able to control the image size our drawings are not compliant and the image breaks the strict guidlines/policy of the brand and if caught we could face serious consequences. This needs to be addressed or users need to be given a secondary way of inserting images in such a way.
@kelly.young @johnsonshiue This is an ok workaround for some cases but definitely is NOT a solution since the image cannot be constrained in anyway to the construction rectangle. In my case, the brand logo is extremely well known and there are very strict guidelines on what we can and cannot do with it and if it were found out that the image/logo was altered beyond those guidelines we could actually be in very big trouble.
@kelly.youngThis works but still is not a solution for us. As I said before, in our particular use case the image/logo is part of an attributed stamp that gets placed on the drawings. We need to have full control over the image at the drawing level.
How about inserting the raster image into a block, and then changing block's x, y or z scale?
Of course that would require some extra calculations (to find the ratio between the new and the old number you want to modify), since it's not as simple as entering a new height, length or width...
"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.
"Interestingly, competitive brands of 'compatible' software will allow raster images to be inserted directly with different x and y scale factors. More interestingly, AutoCAD will honor the different scale factors if you then open the drawing in AutoCAD. Even more interestingly, if you Explode the block back to being an inserted raster image, then AutoCAD still honors the different x and y scale factors.
"And here is another method of importing raster images whose aspect ratio is wrong: Simply open the image in Paint, click on Image, then on Stretch/Skew, and change the Horizontal or Vertical value to correct the problem. Save or Save As, and then import into AutoCAD."
Notes from Cadalyst Tip Patrol: Images in AutoCAD are great; blocks are too. Converting your data (of any type) into a block provides more settings to play with, or at least different ones. Although Bill's tip is a great use of blocks to fix problems, you can also use this tip to create a unique exaggerated view or detail. For example, the changes in elevation on a roadway cross section might not be noticeable. Many sections will have a different vertical scale than the horizontal, in order to exaggerate the changes in elevations. This makes them visible. Draw your section to scale, then block it. Insert it with a different vertical scale!
It is a common conundrum. One gets a legacy drawing on record with the council, and it turns out to be a raster image that has been scanned or photographed, and now the scale is out and/or the aspect ratio distorted. A raster image or a raster PDF has no embedded vector information, and so the software is unable to apportion starting and ending points to the entities that are contained in the image/PDF. While there are tools available to try to convert existing raster images (AutoCAD Raster Tools), the most common method is to trace over the image.
The process of scaling the image is important. In this case, we look at a PDF in Revit LT, although it might just as well be an image or PDF in other packages with the same kind of properties and tools.
Now measure the distance along the Y dimension (if the aspect ratio has been distorted, they will be different). Record the actual distance against the distance indicated by the dimension and calculate the scaling factor that the image scaling factor needs to be multiplied with.
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I am new to the list but I am having some trouble with starting my SWMM model. I have a AutoCAD drawing of all of the storm drains and conduits around Villanova University's campus. It is to true scale and everything matches up with what I measured in the field. However, when I export it from AutoCAD as a metafile and load it as a backdrop in SWMM, there seems to be a scaling issue and the scale is reduced (ie. 28 feet becomes about 22 feet roughly). Is there anything that I can do to solve this problem?
Unfortunately I was unable to match the scale 100%. At the end I approximated the backdrop as much as possible to match the swmm model and after I relocated the nodes one by one to match the backdrop. Is a slow and painful process but couldn't find a better way to do it.