Arrowhead style:
Choose arrowhead style from dropdown
The selection matches SU's linear dimension styles.

Arrow scale
Length of arrow as fraction of the dimension arc radius.
Default 0.05. (0.03 - 0.15 recommended, 0.01 - 0.20 required).

Arc radius:
Set specific radius of dimension arc (as a SU length).
Leave at default of 0 to use distance between first and second pick points.

Arc segments:
Number of segments per 90° in dimension arc
Default 16. (12 - 24 recommended, 8 - 48 required).

Line scale:
Dimension witness line length as fraction of arc radius.

Default 0.05. (0.03 - 0.15 recommended, 0.01 - 0.20 required).

Text scale:
Text height as a fraction of arc radius.
Default 0.10. (0.05 - 0.15 recommended, 0.03 - 0.20 required).

Text height:
Absolute text height (as a SU length). If > 0, overrides Text scale.
Default 0. (no recommended or required value)

Use square mark for 90 °?
If checked, put small square symbol instead of arc and 90° text.

Press {Enter} to redraw last angular dimension with current settings and leave dialogue open.

[Save as Defaults] stores default settings between SU sessions. [Load Defaults] reloads them.

Documentation
JWM/SLB 2016-12-26