For many years and releases I've struggled with the old issue of shifting images in rotated viewports. We use georeferenced aerial photography by way of these images inserted into their own drawing and then Xreffed into another drawing for printing. The issue is, the image appears shifted in some viewports. Most of the time it prints fine but not always. I searched the discussion groups and found a post a few years ago that a reply user stumbled across a quasi workaround. When the view command's Perspective is turned on and then off within the viewport, the image appears to be locked in it's correct position, not shifted. I have successfully used this procedure several times over the years until now. I have half a dozen drawings that when I turn the Perspective on and then off in a viewport, the image will not display. The xref is loaded and the layer is turned on in the viewport but the image doesn't show. Can anyone explain the perspective portion of the view command within a viewport? What I might be doing wrong or what a fix might be? I've read through help for both view and perspective but I can only find definitions. Any help is appreciated.
What I have noticed is if I turn Perspective On and then Off, save my drawing, close CAD, launch CAD again, then open the same drawing, sometimes the image appears.
I won't speak about Perspective, since that isn't my area of expertise, but I will share my suggestions for working around this issue:
1. Do not rotate viewports to angles other than oblique angles (oblique angles are based on 90 degrees, like 0, 90, 180, etc.).
2. Configure your memory usage for raster images by following the instructions here:
3. FDO connect to the Raster image rather than using one of the insert commands to bring it in. FDO provides better memory management. The insert commands load all of the pixels into memory at once - FDO does not.
4. Trim and/or convert SID images to another image type. If you have AutoCAD Raster Design, you can use the tips outlined here:
5. Plot to DWF (but not PDF) rather than printing the Layout to an actual printer. Some users have reported this as a good workaround.
Also, are you using an AutoCAD vertical, such as Map 3D or Civil 3D?
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