Methods for modeling from a photo in perspective?

ned_poreyra

Let's say I want to model something like this and it's the only photo I've got: 

What would be your approach? I'm not used to modeling real objects, so far I mostly modeled from imagination. The only method I know is to find regular geometry (circles/squares) and eyeball-measure everything else in relation to them. So in this case the cutting blade is a perfect cricle and I can see that the body of the tool is about 1/3 of the blade's diameter, 1.5x as long etc. Do you know a better method?

Kanni3d

Can't really do much with perspective references other than judge sizes of elements/proportions, and see extra details. Find the exact make/model, google it to find its spec page (usually manufacturers, vendors, or wikipedia will have it).

From there, you can get it's width/length, and be able to block out the entire tool correctly. From here, you can just eyeball your details, but knowing it fits the proportions well enough that you wouldn't be wildly off.

musashidan

Well, there's never going to be a single image of an everyday object like this. Gather as much ref as you can, study it, and do a rough block in to establish scale relationships early using your artistic judgement. Also, that's a 4 inch or 100mm grinder so now you know the disc dimensions in real life. 

The block in stage is key.