Portal gun version 2.0 WIP
The shells aren't as smooth as I would like, and the rectangular indents in the center section were a pain to work out the placement, but I have spent about 6 hours looking over references and several blueprints/drawings from different sources, and I think I've got it almost completely accurate. The one thing that I know is not accurate, is the chassis section under the main shell. I believe it is an oval cylinder, but several other propmakers have made it round. I'm going to leave it as-is since it is mostly covered anyway, but if you prefer a round cylinder rather than an oval, you can just use a section of pvc pipe for it. No biggie.
It looks like I've almost finished, but I am only halfway. This is going to be a complete set of Portal Gun plans including all of the greeblies, wires, etc. I will have a wire-bending diagram for the little wire cage things on the claw arms, as well as measurements for the cables running to the claws. For electronics, I suggest looking at Volpin's blog (volpinprops.blogspot.com). His awesome work has provided some great references and has been inspiring for me. If you want to scratchbuild your own without pepakura, his blog is essential. He does intense research on a prop before he starts, which makes his props extremely accurate, not to mention extremely well made.
I should have more to show in a week or so. I'm taking a break. I'm starting to see wireframes in my sleep again.