Hi,

I am having some trouble with the Euler bend. The expected length, the bend’s property length_geo, and the length on the mask only match for a 90 degree bend, and otherwise they are all different. I’m using the current Nazca version. Can you advise please?

Sample Code:

```
import nazca as nd
import numpy as np
nd.clear_layers()
nd.add_layer(name='rib', layer=(10,0), fab_name='example', accuracy=0.001)
with nd.Cell(name='top_cell') as top_cell:
#https://en.wikipedia.org/wiki/Euler_spiral
#expected path length: L = 2 * Radius * Angle(rad)
y=0
#The third value in tuples below are approximate lengths I measured from the mask.
for radius,angle,masklength in [(12.5,180,55),(12.5,90,39),(50,90,156),(50,8,47),(50,4,33),(50,2,23.4),(50,1,16.6),(25,1,8.3),(12.5,1,4.1),]:
euler1=nd.euler(width1=1,width2=1,radius=radius,angle=angle,layer='rib').put(0,y,0)
print('Radius/Angle: ({:.1f}/{}) Expected length: {:.2f}, length_geo: {:.2f}, mask measured length: {}'.format(radius,angle,2*radius*angle*np.pi/180, euler1.length_geo,masklength))
y-=5
nd.export_gds(topcells=top_cell,filename='example_081321.gds')
```

Output:

Rad/Angle: (12.5/180) Expected length: 78.54, length_geo: 27.77, mask measured length: 55

Rad/Angle: (12.5/90) Expected length: 39.27, length_geo: 39.27, mask measured length: 39

Rad/Angle: (50.0/90) Expected length: 157.08, length_geo: 157.08, mask measured length: 156

Rad/Angle: (50.0/8) Expected length: 13.96, length_geo: 526.86, mask measured length: 47

Rad/Angle: (50.0/4) Expected length: 6.98, length_geo: 745.09, mask measured length: 33

Rad/Angle: (50.0/2) Expected length: 3.49, length_geo: 1053.72, mask measured length: 23.4

Rad/Angle: (50.0/1) Expected length: 1.75, length_geo: 1490.19, mask measured length: 16.6

Rad/Angle: (25.0/1) Expected length: 0.87, length_geo: 745.09, mask measured length: 8.3

Rad/Angle: (12.5/1) Expected length: 0.44, length_geo: 372.55, mask measured length: 4.1

Thanks, Jon