Hey there, texture is definitely tricky and due to the some of the course material's age there are spots where it could be updated to be a bit clearer. (No promises as to when that will happen just yet but know that we are working on updating a bunch of material when we aren't dealing with critiques and have some ideas that we're experimenting with.)

That being said let's see if I can help clarify some of your misunderstandings.

Dissections we are supposed to study from our references and apply it to our sausage form, only using the shadows the references cast.

This isn't exactly correct. Yes you should be studying your reference and trying to apply the texture to a organic/sausage form but you aren't using the shadows from the reference itself. As explained to you in your previous texture question you should be creating cast shadows based on where you choose to place your light source and your understanding of the texture's forms in 3D space.

i mean, i might be not understanding something, but, fur is pretty much forms instead of shadows, sure there could be shadows deep on the fur, but i do that, i am 100% convinced the result would NOT look anything like fur.

Fur and hair are ultimately just groups of forms, shadow does not exist without a form that blocks light. One thing to remember is that there isn't a one size fits all method for everything and sometimes there is more than one correct answer. In this case fur is a particularly tricky texture to capture because there's so many tiny shadows that people often end up trying to explicitly draw every strand rather than the shadows. While not impossible fur isn't a texture I usually recommend for this exercise, something with larger more easily identifiable forms tends to help prevent students from being overwhelmed (things like scales, tree bark, stones, corn, and berries).

I will also quickly note that just because a texture created from focusing purely on cast shadows may not be easily identifiable that doesn't mean that the attempt itself was a failure. Texture is just one tool of many you can use to create the illusion of something. I'll quickly direct you to this leaf example that comes up in lesson 3, if you were to erase the outer leaf shape and all that remained was the texture in the center you may not necessarily identify it as a leaf at first glance but as you add the leaf's shape, a stem and colour it green people's brains will begin to fill in the gaps more rapidly until they believe it's a leaf. Texture is just one piece of the larger puzzle. Instead of explicitly drawing every detail and overloading a person with too much visual information we want to imply just enough information for them to fill in the gaps themselves and cast shadows allow us to do that very well.

Also, in the lesson, one of the images has a piece of meat that looks really bright, making me wonder what "cast shadows" could i do from there? i mean, the image looks bright enough that i might not have any shadows at all, so what are we really capturing here?

This touches on a few of the things I've brought up already but to quickly readdress them:

• The light and colour in a reference image aren't important for capturing texture. We place our own light and use our understanding of the texture's forms to create cast shadows.

• Meat is another texture that isn't a particularly great one to use in my opinion, people tend to get hung up on changes in colour (especially if there's fat in it). It's definitely possible to use because everything does have a texture it just becomes a matter of getting a picture at a high enough resolution that you can zoom in really close and begin to see changes along the form's surface (pores and fibers in the case of meat).

• If we do manage to find a suitable image then you'd be drawing shadows created based on those pores and fibers, shadows would fill small divots or be cast from raised bumps.

Everything has a texture, but some references look like they cast almost no shadows, in those cases, what can we do? ignore the reference?

It depends on the situation, if the image appears to have no cast shadows because it's evenly lit all round but there's still identifiable forms (maybe it's a picture of the worlds most well lit snake) we can still see that there are forms (scales) and imagine how light would create shadows based on those forms.

If however the image appears like it has no texture and the object is perfectly smooth then it may be a case of the texture isn't a particularly great one to use or you need to find a higher resolution image and get much closer to the object. An orange (fruit) from far enough away or in a low enough resolution image will appear smooth, but the closer you get the more noticeable the pores along it's skin will become.

Hopefully that helped clarify the exercises more, if not I apologize (it's very late in the evening for me currently so my brain isn't functioning at 100% capacity). I will try to drag in Uncomfortable as soon as he's free to either verify my explanation isn't just the ramblings of an exhausted person or to clarify anything he feels I missed/could have explained better.