Number 8. tutorial in my "Nsio explains" series. Talking about foreshortening for continuation from perspective.
Again, I humbly apologize if you found my tone discouraging and offending. I admit that I could have been more considerate.
Way too common mistakes:
Foreshortening is super hard, I admit with that. But it's hard mostly because of the lack of knowledge of how things really look like. That said, if you intend to foreshorten anything, you really need to know your subject rather well. Advanced stuff require advanced understanding. If you don't how the understanding, you will fail miserably, unfortunately.
Probably the most common mistake I encounter is the arm reaching the beholder. Most of the time, people draw the hand in upright position. Well, that's not necessarily an issue, but if you draw the hand in upright position, you need to draw the arm in a way that it's possible for the character to keep her hand in that position. However, people almost always do these two fatal mistakes:
1.The hand is far away from the face
2. The arm is not coming towards the beholder
People usually can draw the hand larger than normally, to indicate it's closer to the beholder. However, the two mistakes I mentioned before destroy the illusion instantly. Let's talk first about the position of the hand. We all know that our arms can reach quite wide area. However, the hand orientation is directly related to the arm position. That said, if the beholder is in front of you and your point your right arm to the right, you just CAN'T turn your palm towards the beholder while keeping the upright position. It's not physically possible. If you point your arm towards the beholder, then your palm can be seen. And when you turn your arm in a position where beholder can see your palm, the hand is relatively close to the face. From the beholder's point of view, that is. Now we can take a look at my illustration where I attempted to draw things as wrong as they can possibly get. See, the hand position is impossible there. So if you really want to draw the hand in upright position towards the beholder and the arm is straight, know that it needs to be close to the face (the face is just a reference point here, easy to remember).
Now on to the second issue I mentioned. Most of the time people don't even draw the arm coming towards the beholder. This makes it look like the poor girl got her hand dismembered. Take a look at the shirt: the opening of the sleeve is obviously pointing downwards.
I drew some other mistakes here as well, but basically they all are one big mistake. I didn't pay any attention to the beholder, viewing angle, not even to the drawing. I just drew individual elements one by one. If you you know that you are drawing like in my bad example, I'll need to ask you: are you really even trying.
I know I know, foreshortening is hard as I already said. But seriously, are you really even trying to understand it and what you are doing? Are you putting any serious effort in drawing at all? And are you reading this tutorial in hopes of getting easy way of drawing foreshortening?
Unfortunately, I have no magic tricks to offer. There are no shortcuts to experience and understanding. While this tutorial may help you to give some insight about the matter, you won't learn foreshortening unless you really give it all you got. And in order to draw foreshortening, you will need to learn seeing things the way they are, not the way you think they are. You must acknowledge that it's you that need to see the effort, do the studies, do the practice, learn from references and stuff.
Now, I wouldn't say that I'm perfect with foreshortening. I had plenty of problems to compile this tutorial, but at least I can say that I gave it all I got. And in fact, I think I learned a bit more about drawing foreshortening. This was valuable practice for me.
What is it really?
Foreshortening is a term for procedure, where the subject is drawn in perspective and coming towards the beholder. The subject is literally "shortened" to gain the illusion of depth. Usually perspective guides don't work very well with foreshortening, so it's mostly about trusting one's perception and doing decent guesses. And that's often enough, because it doesn't have to be perfect in order to look right. To draw anything foreshortened, you will need to have rather good understanding about shapes and proportions in three dimensional space.
I usually draw section planes and draw "middle lines" on top of the shape surface to analyse it's orientation and form. For example, if you draw a cylinder in any angle, you will need to be able to tell it's height in any given time. Even when the object is foreshortened, you need to know that the height of the objects remains the same.
How much smaller it should be?
As we already know, things look smaller the farther the are. The same principle apply with the foreshortening. However, you will need to know how far the object actually can reach and deduce how much smaller it really gets. If the object is very close or it's really large, it may look distorted. This distortion happens because of our vision (fish-eye). The more complex the subject of drawing is, the harder it gets to draw it foreshortened. Basically it means that you will need to study references and live models to gain understanding and knowledge about how things really look and then base your guesses on that.
Applying the cylinder example
The cylinder example seen on the tutorial can be applied on anything. The arm is probably the most straightforward subject to apply the example. All you need to do is to imagine that the arm is made of a pair of cylinders connected with spheres as joints. Then you will just need to draw the cylinders in a manner that they look like they were foreshortened. This sounds much easier than it really is, but using cylinders makes it a tad easier. Of course, if you don't know how to draw cylinders in the first place, then you can probably consider a bit easier matters to practice for the time being.
I drew some more complicated shapes than simple cylinders. To do this I had to draw few projections first in order to have the necessary references to draw the foreshortening. That said, I really recommend drawing projections of things that you are attempting to draw in perspective so that you know how they really look and you have references to look at while you draw the perspective. I must say, I hardly ever draw such demanding foreshortened drawings, so these really got me to the edge. I'm rather satisfied with the results though and this was super useful practice for me, as I mentioned before.
Some practice to try
I usually draw this kind of practice when I feel bored or I have gotten rusty. Anyway, the point is that you draw few circles, gradually changing their size from large to small (large ones are close, smaller ones farther). Then you will connect these circles with two lines in the same order you drew the circles. Now you will need to erase the circles partially to give it three dimensional look and make it look like a cable or a worm. If you have a lot of patience, you can draw quite complex thread of these cables.