Annoying New Materials Tab After Upload Shows Only Half Of The Materials

Very dissapointing, don't 'fix' something that worked!

Agreed!
Harder to look at things, and to see if something is printable you have to click into each tab now.

Make the clickies stickies!

Considering that the complete page markup is downloaded on initial load anyway, I would suggest a "Show All" button. It is incredibly annoying to click on a material, review what's shown, scroll back up to the top, and repeat for every single material.

There are times when I design a model for use with a specific material, but I'll scroll down to see if other materials are already compatible and affordable to also offer for sale.

Another approach: to reduce user clicks (and scrolling up), you could show all materials as you did before, but still include the new material buttons at the top. When the page scrolls down, you could have a smaller version of the material tabs scroll with the page, such that it's always visible. At this point, the purpose of material buttons would simply be to scroll directly to that section.

Another another approach: If you think that showing all materials at once is too much, then allow the users to toggle on and off the materials for which the model was designed. Not only that, but persist the selection for that model such that the next time the user views the model, the same materials are shown / hidden as the last time. As an example, I may have a pendant that was designed for metals, but not plastics or sandstone. Once I choose which materials I want (in this case, metals), only show those materials from then on.

In a previous incarnation of this you could toggle material families for display on the model page. I believe it started out with all materials showing and then you could turn off the ones you didn't want displayed.

Why some of these things repeatedly come and go is a complete mystery. All I can guess is that there are sometimes concerns about the short attention spans people have acquired. It's as if too much information might induce modern humans to spazz-out, tune-out, and drop-out or something. Putting everything into bite-size nuggets could certainly be an option but so should being able to view longer and more comprehensive lists. The show all button in such situations should be a given.

The same sort of thing also applies to the product page. I prefer to select all materials as possible selling candidates (aka the default material list) but that again means clicking on each material group over there. I set my final selling choices on the lower list that includes the eyeball clicky on the right side. If you do this right off the bat it makes things easier to activate a requested material without having to again search through the initial selection list and then follow up on the final sales list. And if I could have previously set my default mark-up value when creating the selling list a single click on the eyeball would have been sufficient to do everything needed to make a material option sellable.