Hi @younchen, nice drawing! Yeah, the forarms, and the flexors especially if you ask me, are really tricky. The muscles are many and hard to see, so you have to rely much on your knowledge about the muscles. Do you feel like you know the muscles well? Their forms and attachments? I think you would really benefit from doing constructional drawings of the forearm from different angles and in different poses, drawing from imagination, but refering to reference to make things look right. Think of it like you're getting to know a machine. I attached an image with examples of how your studies might look. There are no rules really. The point is to get to know the muscles well, and what exercise you have to do for that depends on the situation. Sometimes drawing from imagination is what you have to do, sometimes drawing from reference, sometimes doing a tracing, sometimes etc. - In Stan's demo, notice how the muscles he draws aim toward their attachments. In the brachioradialis for example in your drawing, you show its borders with a curved line, that doesn't aim toward the insertion. A similar thing happens with the bump you've drawn on the under side of the arm. The bump you see on the reference is a combination of the flexor digitorum and the flexor carpi ulnaris, I think. Their origins are back at the olecranon and medial epicondyle of the humerus, so make sure to aim the bump that way. Hope this helps :) Keep up the good work!

Thanks for your note and beautiful drawing

If you were to combine what you did here with the first attempt, it would be great... In the first attempt you shaded the arm essentially like a cylinder (i.e. you were thinking about primary forms). In this one, you seem to have forgotten about the primary form, and only considered the secondary forms in isolation. I think Stan once said that when he's shading, he's not shading the primary form first, but he's thinking about the primary form while shading the secondary.