Circles not smoothe, but jagged?

Hey all,
I recently upgraded my makerbot replicator dual firmware to sailfish and have been loving the improvements.
I am however noticing an issue that I'm having trouble fixing.

My circles over a certain size seem to be very...geometricly basic. Even on some standard curves I can see the same issue. The circles are no longer perfectly circular, I have very visible facets.
[dl.dropbox.com] Is a large item I'm currently printing that takes most of the print bed...is this normal for large scale objects? Or is there something else going on? It seems to be very loud when making the circles but I figure that was normal since it's jogging xyxyxyxyx.

Any help is sure appreciated!

... the 'circles' in a STL object are mostly built with triangles and when outputting the sections, it's combined from short line segments, so this is to be expected.

AFAIK there are some softwares, that try to fit curves in such line-chains, but most wll export them as lines.

Without look-ahead the firmware will de-/accelerate at start/end of a line, so the filament at the connecting points is thicker as in the middle of a line, what's forcing this 'jagged' finishing too.

You can try to rise the geometrical accuracy of the objects and/or generated curves, so this segments will be shorter, or reduce the printing speed, so the influence of acceleration will be reduced ...

Edited 1 time(s). Last edit at 01/09/2013 08:17AM by VDX.

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Viktor
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Thank you! I'll try changing the export settings in my modeling software.