This was previously asked some time ago in https://communities.bentley.com/products/microstation/f/microstation-forum/133514/raster-not-showing-in-dwg-file-opened-on-v8i-but-shows-in-autocad?ReplySortBy=CreatedDate&ReplySortOrder=Descending ... but no answer given.
I solved it partially - but is there a better fix?
This bugged me for a long time without finding an answer - until now. In a test, I saved a DGN with a 1-bit (mono) raster attachment as a DWG. I opened the DWG in Autocad - all good. I opened that same DWG in Microstation and the image was not visible. However, with mouse over the boundary of the image, I could see the outline. From there, i selected the "i" for information properties. For some reason, under the "Color" properties color "Index 1" is set to black 0,0,0. On a black sheet background it is black on black, which is not visible. By changing the color to white or changing the sheet background to white, it is visible.
Is there any way to make it automatically open with "Index 1" being white 255,255,255 - as it was in the original DGN from which the DWG was created?
We are receiving many vendor drawings created in Autocad supplied in DWG with raster attachments - 1-bit mono (black and white) as per the company's requirements. It means they don't show up unless the black sheet background is changed or the *many* vendor drawings are edited to change the "Index 1" color. As stated, the mono raster has no problems displaying when referencing the raster image into a new DGN file.