Received 3 or 4 color STL
I received a STL file that I want to print. How do I know what heads are being pulled and how can I determine what colors are on which head. The new slicer won't open a STL file.
RE: Received 3 or 4 color STL
If you can't open the STL in PrusaSlicer then the question is kinda moot until that is solved. What is happening when you try to open it? Is the STL available somewhere others can try it for you?
As far as the question itself. You assign extruders to parts, each of which is a separate STL. There are two ways you can import the object. The easiest is to have the MMU selected as your printer, click the add button, select all the files for the object and import them. It will recognize the files as a single object and offer to import them as such, let it do so. The other option is to import the first part, right click on it, select add part, add the next part, then repeat for all parts.
Either way, once all parts are imported for the object, look in the object list on the right and you should see a column that shows what extruder is being used for each part. Adjust those settings as desired and then load the desired filaments to the appropriate tool paths.
RE: Received 3 or 4 color STL
I realize now I have worded this wrong. I received the gcode not the STL.
RE: Received 3 or 4 color STL
Ahh.. PrusaSlicer won't load gcode except to read configuration information if it is available. You simply give it to the printer (SD Card, Octoprint, etc..). There are gcode visualizers out there (like gcode.ws), but I don't know of one that takes multiple extruders into account. So there really isn't an easy way to tell what tool was used for what areas. If you are familiar with the model you can look through the gcode for the T commands (T0, T1, T2, T3, and T4) to tell you which tool path is being used (0 = 1 and 4 = 5), then you could plan your colors accordingly.
Generally speaking, however, if you don't absolutely trust the source of the gcode I would strongly suggest against printing it. Even if you discount nefarious intentions, the gcode can be tuned for filaments or other factors that do not apply to your case. Such things could simply lead to failed prints or to more serious issues.