Hi everyone there,
I know Impression has benn long forgotten by autodesk, but I keep using it as it is a great tool for my everday work as a Cad artist. This is why I'd like to share some tips on block creation process, for those who dont know how to do it, I found an easy way to get it working:
Just keep in mind, you MUST create a PNG file from the image file you want to use, this is because the background of your image file MUST be transparent. Also, PNG files is the format Impression uses to store block data, although the library files that links these PNG are in IRF format.
Let's say we want to create a block for a tree, aerial view, and we'll supose you already have the exact image you want to use (in jpeg or other format, doesn't matter). Just photoshop and open your tree image, and select the tree with any of the selection helpers (if it's not on a white background) or just use the magic wand to select all the white border of the image (if it's on a white background) and then use the inverse selection tool on the edit menu.
Then, just tap CTRL+C to copy your selection (or EDIT menu --- copy) and the Jump to impression, and then press CTRL+V to paste your image. Easy as it comes, hit B on your keyboard (or right click --- create block from selection) to add the image to your library as a block, and VOILA! It will be be on your library when you need it.
Just one more coment, try to keep the image size (of the things you want to use as blocks) reasonable, for example, an aerial view of a tree is 375x375 px or so. You can check other relative sizes on your library folder for reference.
Hope this will be of use for some of you.