What happens if a DWG image is not located in the XY plane? — Though 3D display is fully supported, some restrictions do apply for the modify, mirror, warp and clip functions. They require the rasters to be attached parallel to the DGN's X-Y plane in order to be effective in a 3D DGN. If the raster is not parallel to the X-Y plane, these functions will be disabled for raster manipulations.
What happens if an image has a self-intersecting clip polygon? — For the time being, when loading a DWG file with such a polygon, MicroStation ties this clip polygon to the image attachment, but the rendered image does not show clipping at all, even though the clipping data has been transferred. This is done so that no data is lost when switching from one platform to the other. On the other hand, if an image has a self-intersecting clip polygon and the user decides to set a new clip polygon on the image, the original (and invisible to the MicroStation user) clip boundary is deleted and replaced with the new one.
What happens with an unsupported image file type? — When loading a DWG file containing an unsupported image file type in MicroStation, the image appears in Raster Manager's image list, but with the mention "Raster cannot be read." Even though Raster Manager will allow the modification of this image's properties, the modifications will not be saved to the DWG file.
What happens if an image file cannot be found? — When loading an image file attached in a DWG file that cannot be found from the filename information contained in the DWG entity, the image also appears in Raster Manager's image list, but with the mention "Raster not found." Because of its missing status, the image file type is unknown. When this happens, the image's color mode is forced to RGB. The same limitations on modifications stand when this case arises as when an unsupported image file type is loaded in MicroStation (that is, no changes are recorded).
