5D
As I mentioned in my last post I’ve started work on what I call Volumetric 5D, which is an extension to 5D. I realized, however, that I wasn’t even sure of what 5D was.
I did some research before getting started but couldn’t find a good definition of “5D.” I found in the code for the Dimension plug-in of Skeinforge a reference to this article by Adrian Bowyer on the RepRap blog about “4D,” but there was no mention of a 5D.
I still haven’t found a non-code explanation of 5D.
What is 5D?
First, 3D: X (left and right), Y (front and back), and Z (up and down).
Then, as explained in the article on the RepRap blog, 4D: 3D + E (filament to extrude).
So, what’s the 5th D? I can’t tell you for sure — I couldn’t write the Wikipedia article on it because I only have circumstantial evidence and no references — but I believe it’s F (feed rate).
I had to look at the RepRap 5D firmware to get that. It makes sense when you look at GCode, kinda, but it didn’t really make sense until I saw how it’s implemented.
Feed rate is how fast the head is traveling in relation to the build platform. In the 5D firmware it’s implemented as a virtual stepper where the current position is used for how long to pause between steps of the syncronized movement of all of the stepper motors.
As the movement continues toward the destination (in physical space) the pause is also moved along a linear path from the previous speed to the destination speed. The end effect is an acceleration or deceleration from one feed rate to another providing a (theoretically) less jarring switch from one feed rate to the next.
So, there you have it, all five Ds.
-Rob
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