AutoCAD Ques: Print Black With Red&Blue Overlay
 

I'm hoping someone can help me with this one as I couldnt find the answer using Google.

I have 2 drawings that I want to overlay and compare. I want to make the old drawing entirely Red, and the new drawing entirely Blue. When I overlay them, I want to plot it off so that everything that has NOT changed, will come out as Black (Red+Blue=Black when mixed together I believe), where the differences will show in Red & Blue when overlayed.

I've been told this can be, and has been done before, but have no idea how to go about it. Hoping someone with more CAD experience than me knows how to do this, TIA.

It sounds like it can be done. Make each drawing into a block. Change the color of all the entities in one block to the color you want. Insert the blocks into a new drawing. Move one block onto the other block. Snap two common intersection to each other.

You won't get black however. Your color logic is flawed.

thanks for the reply.

But if i place 2 blocks on top of the other, won't it just plot off the object that is currently shown on top and it's associated colour?

that's the problem i'm currently encountering. If I send Red block to back, it will plot Blue. If I send Blue block to back, it will plot Red. I'm not sure how I can get the printer to plot both of them and their associated colours at the same time :(

It depends what your pen settings are also. If the block in behind is set at one colour and it has a thicker pen setting then the the block on top, they should both print out then. You just need to make sure the pen settings for the block in behind are thicker then the block on top. That should do it for you.

thanks for the reply. i can't print from home so I'll try plotting w/ diff pen settings at work. However in print preview it didn't seem to work either. It just showed the colour of the object in the background outlining the colour of the object in the foreground...no black

The colours won't blend, they'll just be one on top of the other. The red + blue won't equal to black.