topic Re: What takes up more computing resources, lines or arcs? in AutoCAD Forum

AutoCAD - What takes up more computing resources, lines or arcs?

paul.riebeKGF5E — Thu, 29 Sep 2022 15:57:00 GMT

I've noticed that most blocks imported from PDF's are actually a mass of short lines all linked up to create curves. It seems to me that this would take more processing power and memory than an arc. What is the resource tradeoff between a line and an arc in terms of AutoCAD's calculations? I'm curious if there is a point at which multiple lines take more memory or processing power than a single curve. My intuition tells me that there probably are, although it might be negligible.

[ The subject line of this post has been edited to include the product name by @handjonathan ]

Re: What takes up more computing resources, lines or arcs?

RobDraw — Mon, 26 Sep 2022 21:56:39 GMT

Graphics resolution can be measured by how many lines are used to represent a given curve. The way I understand it is that a computer cannot "draw" a true curve. Maybe it's a limitation of computer power or just the way current graphics work.

Geometrically, an arc or a circle is quite easy. Other kinds of curves become quite complex.

So, I think the answer to your question is it's a matter of your point of view.

Re: What takes up more computing resources, lines or arcs?

Kent1Cooper — Tue, 27 Sep 2022 12:45:18 GMT

A set of Lines making up an approximation of an arc definitely consumes more memory than an Arc. There are elements that are stored in common for all object types [Layer, etc.]. Beyond those, the difference would be in how much information needs to be stored for a given object. Each Line requires just two point-list entries, for its ends. An Arc requires a center point, a radius, and a starting and ending angle. That's four entries for an Arc, compared to two for a Line, but each of those for the Line involves four numbers, whereas for the Arc, only one does, and the rest are only two numbers each. So it may be that two Lines take less memory than one Arc, but certainly with more than that, the Lines take more.

Lines [and Arcs] joined into lightweight Polylines with more than just two or three segments take less than the independent pieces, because those common things [Layer, etc.] need to be stored only once, not separately for each piece.

Of course, in your image, there are not many stretches of short Lines that would look right as Arcs -- it's a compromise between fidelity to a shape and memory consumption, if that's even really a concern these days. But if you haven't already, at least connect them into Polylines as much as you can.

Re: What takes up more computing resources, lines or arcs?

paul.riebeKGF5E — Tue, 27 Sep 2022 17:45:53 GMT

Kent,

Thank you very much! That pretty much confirms what I was thinking. Thank you very much, that makes a lot of sense. I appreciate the advice about polylines.