My partner picked out this color-changing filament on our trip to Microcenter yesterday. It’s an Inland PLA called Rainbow 2. There was a regular Rainbow filament also, but it had more muted colors, which is why they made a second I guess.
The color change is pre-determined and has an amount between each change. Due to this, you do need to print a larger object or multiple smaller objects to get a color change. With this knowledge, she ended up picking a vase so it would definitely get at least one color change.
Here is a link to the vase she picked on Thingiverse. It does have some recommendations for settings that I used in Cura. The print was estimated to take 141g of filament and a bit over 11 hours for me. The walls are pretty thin which is why it used so little filament.
It turned out great! We only really got two color changes out of it. The bed layer is technically purple but you can’t really tell so we got a green color into yellow with the transition happening as it tapered up. I think we got lucky with the transition and are very pleased with it.
As you may guess there are a lot of variables to consider with color-changing filament such as how often it changes and the lack of control as to when it changes or what it changes to. You could try and plan/predict it by estimating how much filament to get to a point and how much filament to the next color change on the roll but that sounds like a lot of work for something where the math could be off.
I have seen other brands of filament advertising fast color changing where it would work better on smaller objects but the brands I don’t know that well and worry about quality, and ease of printing with the material. But it’s something to consider as well as printing multiples at the same time.