Segment Angle

[Martin A]

Hi all, just courious as to why the segment angle for open segment bowls is 1 deg. less per side than closeded segments.
Example: 48 segment close =3.75 deg.
48 segment open = 2.75 deg.

 

[mfisher]

The reason the miter angle is different is to account for the gap in the open segment bowl

Closed Segments: 360 / segments / 2
Example for 12 segments: 360 / 12 / 2 = 15 degrees

Open Segments: (360 - (segments * gap)) / segments / 2
Example for 12 segments with 8 degree gaps: 360 - (12 * 8) / 12 / 2 = 264 / 12 / 2 = 11 degrees

If memory serves me correctly the about is what the software uses to calculate miter angle.

 

[Martin A]

Oh I see, so rather than just shrink the segment width you use an angle to set the gap so it gets wider or narrower as the dia. changes.

 

[mfisher]

Pretty much.
What is great is WTP does the calculations for you. You have two options in setting the gap: set the degree you want or the actual size of the gap.
- In the Project Properties (right hand side column)
check the box on "Open Segments are X". set the degree you want.
if you want to use dimensions then uncheck the box and
on the left side in the Row Detail box, in the Outside Open Space enter the dimension you want the gap to be.