PDA

View Full Version : Antialiasing


hamed
01-20-2003, 09:52 PM
Hi,

I have a problem with my 3d programs.(Max/LW).
When I working in Max or LW viewport and working on a model
when pressing special key for viewing place of segments,all of them
seems to break.I means: "No straight line".
I think the reason of this is Antialiasing in my card,But I'm not sure.
Could anyone tell me the major reason/s of that?because I hate breaked line.
Which cards (Especially Redeon Card,has the best Antialiasing for 3D).
Any image in segment mode of a 3d model would be greatly appreciated.
(with Redeon Cards).

I'm using Redeon 8500.


Thanks.

elvis
01-20-2003, 11:11 PM
video signals are pixel based. pixels are aligned in a grid on your screen, and as such if a line is not perfectly horizontal or vertical, you get the stair-stepping "break" you mention above, which is called aliasing.

anti-aliasing is a method where video cards attempt to reduce this effect. there are a few ways of doing this, the most common is sampling a scene (or part of a scene, or just a line) at a higher rate, and interpolating (or guessing) what the bits in between the aliases should be. then, by using a colour that is part way between the background colour and the aliased line, fill it in.

this effect fools the eye into thinking the line is much smoother.

the side-effect is that lines when anti-aliased appear a little blurred, and thincker than normal. i'd much rather see aliases than fat lines, especially when going for accuracy in modelling (which is 99% of my company's work as an architecture firm).

which card is "best" for anti-aliasing (AA) is a hard question to answer. radeon cards typically have less of a performance hit when performing full scene AA compared to other cards on the market, but neither radeon nor geforce cards have the ability to do hardware line AA. for that you need a professional card like the fireGL or quadro cards.

the card you are using is a gaming card at heart, and won't do as well in CAD. you can certainly turn on wireframe AA in your openGL options in Max (no idea about LW, sorry).

CGTalk Moderation
01-14-2006, 05:00 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.