Hey everyone, I’m about to start on my first real project. It’s going to be an animation about a wooden drawing manikin and an old 90s barbie doll I found in my room. (no, I’m not a girl, my grandmother got me it when I was four so I would stop playing with my mom’s hair all the time :p) Anyways, I’m really OCD, and I want them to have accurate dimensions. What would be the best way to get reference images of them? I just took some, but they weren’t very good because the angles weren’t aligned right for an orthographic view. How many of you have taken your own guide images, and what’s the best way to take them in your experience? Should I just use the actual manikin/Barbie to model it?
The level of accuracy you want is not possible to gain using reference photos alone.
A photo contains perspective and lens distortion that you can’t compensate accurately (enough) while modeling. It’s a snapshot of 3D world. 2D drawing (like technical drawing / cross-section) gives better reference for measurements because it doesn’t contain those flaws.
You could try to match Blender camera to the one that you take the photos with but that’s only a rough estimation of the size and is done in perspective.
I’ve taken reference photos of furniture and household equipment and used those just to get an idea how everything looks and pointers of the dimensions. For example, there was couple of known products and I tracked their spesifications to get accurate dimensions. Also, there are known sizes for some things. Combining these known dimensions and information I was able to get pretty accurate dimensions for the unknown ones.
Another precision modeling exercise I did with my brother was a Logitech speaker. To get the dimensions we used pen, paper, and a pair of calipers. No photos. Measurement error for that thing is ±0.25mm and most of it is in the back where there’s a cavity and a holder for the wire and we couldn’t get the calipers to fit in there well enough.
You need to decide what is accurate enough. If an estimation is not enough, you can’t trust the photos alone, there has to be numbers you deal with. Measurements of the known points.
Okay, thanks, I think I’ll do that. I’ll just get measurements of the main parts, like hips/chest/waist/etc. I’ll just feel kind of funny measuring a Barbie’s body 
Print out a reference grid, put it under the models. If you have a tripod and a t-square or level you can attempt to set your camera up like a pencil test station… otherwise you’ll have to try to correct the lens distortion using the grids. (Use .5" or 1" grids). When taking the picture from the side, take 2 pictures… 1 with the arm down and one with it straight up or some other pose so you can see the waist if it was obscured. You might also want to tie the hair up (or braid it ) so that you can see the back/neck/shoulders/etc.
Best of luck.
Try using a scanner. I’ve seen a top modeller use a scanner to get reference images for a model car. If you do use photos use the longest lens you can - the longer the lens (focal length) the closer it is to orthographic. Actually it’s not the focal length per se, but how far away you are from the subject. With todays high megapixel cameras you could photograph the subject from a fair distance even with a normal lens, and then crop.
Wow, these are all really great ideas. I have a scanner, so I may try that. I think it would probably work best for me since all I have is a phone camera.
Okay, well my scanner isn’t big enough, although I guess I could scan different parts and then stitch it together in gimp. I just tried drawing it out, and… well… it was bad. I think what I’ll do is just take measurements and go from there. I’ll just have to deal with my OCD, I guess :P.
But then aren’t you just magnifying the distorted picture? I would imagine you would need to take care of lens distortion during the picture-taking process as much as possible.
I think the ‘lens distortion’ that people mention is actually perspective distortion. Taking the picture from a distance reduces this, and cropping won’t magnify it. How big an image does one need for reference? 1 k square? (1 MP).