Segmenting a circle

hellnbak · 28 Oct 2010, 21:59

Is there a reason why the "round" objects in so many models in the warehouse are so obviously not round but instead have a bunch of sides? Is there a downside to increasing the segments of a circle to make it smoother? thanks in advance

Rich O Brien · 28 Oct 2010, 22:10

increasing segments will increase faces which will impact performance. But if your rendering there are tricks and tips for this. It's a balancing act really!

Gaieus · 29 Oct 2010, 08:14

For a 3D tree that is showing in mid or far distance, even the default 24 segments would be a killer for your machine if you draw the trunk and branches with them. Often 8 or even 6 segments (or maybe even less) would do especially with a good bark texture properly mapped.

For a close-up shot of a car wheel, you may want to increase the segments however. It's always up to what your purpose is actually. You can even make low and high poly variations for your objects to optimize performance.

thomthom · 29 Oct 2010, 08:35

@hellnbak said:

Is there a reason why the "round" objects in so many models in the warehouse are so obviously not round but instead have a bunch of sides?

SketchUp doesn't have true circles - they will allays be segmented due to the nature of the modelling engine. Use only as many edges you need to make your objects appear round, from the points of view you will be using for your model.

Dave R · 29 Oct 2010, 10:59

As Thomas writes, "Use only as many edges as you need..." A small hole can look round with relatively few sides while something like a round table top would benefit from having more sides. The same goes for arcs. A small round over will look fine with three or four sides but a larger curves need more.

Don't waste geometry where it isn't needed but don't skimp where it is.

In models you find in the 3D Warehouse, it could be they are drawn with few sides on circles and arcs to keep file size down. This is the case with many of the components from the @Last days. It could also be they were drawn by someone who didn't know how to control and utilize the tools well or they were just sloppy. With the Warehouse you get all sorts.