3d printing firmware extruder help

[3dkarma]

Hello

I am developing my own 3d printing software and have trouble with the extruder.
I have read that the gcode g1 command moves to the given position.
but there is also a E paramenter which pulls out the given amount of fillament from begin to end.
But is this function needed?
If yes:why?

Take a look at the G Code reference at the reprap wiki. G1 commands a move, but you also need to tell the printer what to move. G1 E tells the printer to extrude; G1 X tells the printer to move in the X axis, and so on. http://reprap.org/wiki/G-code#G0_.26_G1:_Move

Hello
Or Can i just make it that the speed of it is set To match the speed of the x and y and z axis.
Or will my 3d prints than be incorrectly printed?

You can't make them all move at the same speed. This all has to do with the steps per mm of each axis. While the X and Z axes will most likely take the same amount of steps, or movements of the stepper motors, to move a given distance, the Z axis will take a different number of steps and the extruder will need to take its own number of steps to extrude a given amount of filament. You use the M92 command to set the steps per mm for each axis.

What type of software are you writing? Printer firmware or something else? If you're going to get it to work with other software (slicers and the like), you'll need to get it to support the set of G Code commands properly.