# Question about Polar Reference Point

Sofistik 2024-1.

According to Aqua manual Pg.3-191
Case 2: Polar References
REF PT0 ∼PTD absolute coordinates
REF PT0 +PTD afﬁne scaling only along direction

``````POLY O
VERT   1    0   0
VERT   2    10  0
VERT   3    5   5   REFP 1 ~2

POLY O
VERT   11    0   10
VERT   12    10  0  REFP 11
VERT   13    0.5   5   REFP 11 +12
``````

I expext point 3 has Y=5, due to REFP 1 ~2
and point 13 has Y=0.5*10=5, due to REFP 11 +12

But point 13 Y=0.5, Why?

Reference Point.dat (475 Bytes)

Hi netsonic,

“Affine scaling” means the offset distance is relative to the length between point 11 and 12.
If the distance between point 11 and 12 is variable and variies between 10 and 15, for example, the y coordinate of point 13 will change from 0,5 to 0,5*15/10 = 0,75.

https://docs.sofistik.com/2023/en/sofiplus/cmdref/cross_section_editor/aligned_polar_references.html#example

Best regards,

Nora

Hi Nora,
Thank you.
Looks like there is no way to define a point using “relative distance” instead of “absolute distance”

Hello,

in addition to the answer from Nora, we have extended the description of the polar references as well as the construction references in the AQUA manual for the next service pack 2024-2. The description in the Cross Section Editor documentation has also been improved.
The sample data sets will then also be available with the installation: TEDDY → Examples → aqua.

Best regards
Sabine Fahrendholz
Senior Product Manager

Hello,

The ∼PTD or +PTD defines absolute distance between PT0 and the target point.
In the real practice, we want to define relative distance, instead of absolute distance, between PT0 and the target point.
E.g. I want to define mid point between PT0 and PTD, I need to input 0.5
Can this be done in the future version?

Hello,

currently, it is not possible to define the mid point relative between PT0 and PTD, e.g. with a relativ definition between 0 and 1. I notice this as a wish and we will discuss this topic in the team.

Best regards
Sabine

1 Like