# FSUT (Friday SketchUp Tip)



## SketchUp Guru (22 Aug 2006)

I guess it has been awhile since I posted any FSUTs and although it is only Tuesday here in Minnesota it must surely be Friday somewhere in the world so here is the latest. I hope it isn't a repeat. 

Since it might not be very clear as to what the real tip is, it is about how to simulate a detail without actually creating it in an efforet to keep file size down.

Attached is a quick drawing showing two methods of creating a roundover appearance on a table leg. Of course this method doesn't only apply to table legs. The legs are drawn at 1 1/2" square. On the right I used arcs with a 1/8" radius. I set the number of segments in the arcs to 6. This leg has 84 edges and 30 faces.

The left leg shows the start of a different method. I copied the edge line onto the adjoining faces. I set the lines 1/8" away from the edge. After repeating that all the way around, I softened the corner (Ctrl+Eraser tool) and hid the offset lines (Shift+Eraser tool). I ended up with a leg with only 36 edges and 14 faces.






For a single leg the segment and face counts aren't very important but in a larger, more complex model this can easily become an issue for your video card.

Here is a more complex model as an example. The file is 1.3Mb. It has 55674 edges and 22041. Although there are many repeated elements (169 component instances) there are only 29 component definitions which helps to keep the edge and segment counts "low". It still loads up the video card's RAM on this computer.





Hopefully this is useful for someone. Cheers.


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## Steve Maskery (23 Aug 2006)

Dave R":1cgnlh8l said:


> Hopefully this is useful for someone.



It certainly is! Thanks Dave.


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## Johnboy (23 Aug 2006)

Hi Dave, interesting stuff as usual. Any idea why Sketchup creates so many faces? Other CAD programs I use only make 10 faces for a leg like this (four flat sides, four fillets and two ends).

John


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## Steve Maskery (23 Aug 2006)

John
It's because SU doesn't do proper arcs, it does polygon segments. Those fillets are several straight lines which approximate to an arc, and each one becomes a small face.


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## SketchUp Guru (23 Aug 2006)

Steve, I'm glad it was useful.

Johnboy, Steve is correct. I believe that when SU was first in development the decision was made to use small line segments to approximate curves in an effort to improve speed when rendering the resulting faces. Keep in mind that SU was not designed to be a CAD program. It was intended as a sketching application for architects. Something like sketching on a napkin with a felt tip pen. The creators of the software fully intended that the sketches would get moved to a full blown CAD application to get all the detail work done. At that point the short segments would get replaced with real curves. SU's ease of use has certainly made it popular with many folks who choose to use it more like a CAD program than a sketching program.


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## Johnboy (24 Aug 2006)

Thanks Steve and Dave. I still don't understand how having lots of flat faces makes it faster than one curved face but then it is just one more thing to add to the list of things I don't understand 

John


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