Hi @amirace77 – Based on my experience I do not agree with the idea that tracing does not build skill. In fact I’ve found tracing to build skill both when I illustrated as a kid and sculpting now.
At a beginner level, tracing can be thought of as training wheels on a bicycle. Once a beginner traces enough, they can “remove the training wheels” and draw/sculpt without the underlying image to trace.
At an intermediate-to-advanced level, tracing becomes another tool in the tool box. Whether you want to sculpt a perfectly accurate 3D version of 2D art or want to double check proportions, tracing is definitely a useful utility.
That said, too much tracing can be too much of a good thing. For artists that lean too much on tracing and never “remove the training wheels” it can certainly be a crutch. In that way it can hinder the building of skill.
is there an alternative way to get the proportions right?
Some teachers come up with proportional formula’s to aid shape formation. I think these can be helpful but in my experience familiarity is the best way to use/trace reference less. I should also say that formula’s work better for realistic proportions and not so much with stylized things. With stylization based on concept art, the art should be the bible of the project.