# R or @ in Rhino

Hello!
Can anyone attach a good video on using r / @ in Rhino? Well, or describe in detail? I just faintly understand this …

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Well, however, it is very brief there, and I do not understand, for example, such a form r1<60
I think this definition of a circle through a radius of 1 relative to the last point at a specified angle, but this is only an assumption. Yes and <number usually works differently!

1<60 is a polar coordinate. Distance 1 from the CPlane origin and angle 60 degrees from the x axis of the CPlane.

“R” in front of a coordinate means a Relative coordinate with the distances measured from the last point. For a polar coordinate the angle is measured from the CPlane x axis. (The “R” is not related to radius.)

“w” in front of a coordinate means a coordinate in the world coordinate system.

See the Level 1 Manual for more information on Rhino coordinate systems. https://www.rhino3d.com/tutorials

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Ooh, okay, thank you!

Here’s a direct link to the part of the Help file that covers this subject:
http://docs.mcneel.com/rhino/6/help/en-us/index.htm#user_interface/accurate_modeling.htm

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@John_Brock Unfortunately that document only mentions polar coordinates (as well as spherical and surveyor coordinates) a section with a large bold title of Cartesian coordinates. Other types of coordinate are only covered as examples. There is no explicit explanation of polar coordinates, etc. The document should be revised with a section title such as Coordinate systems and explicit explanations of each type of coordinate, not only Cartesian coordinates.

If you keep scrolling, there’s a section on “World Coordinates” and “Relative Coordinates”, as well as “Elevator Mode” and a bunch of other subjects. It’s true that polar coordinates are also listed.

Only as “Examples” without any explanation. .

Is this better or different?
http://docs.mcneel.com/rhino/6/usersguide/en-us/index.htm#html/ch-05_accuratemodeling.htm%3FTocPath%3D_____5

Different. No description of how the polar and spherical coordinate works in Rhino. It is obvious once you know how it works but not to the novice.

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I already know more than 4 sites (doc) on Rhino, and all are somewhat different from each other. Here @brian has attached a site that I seem to know, however I feel some difference. What’s the matter? Why so many sites? I’m already confused in this heap … And which site is really correct and relevant?

All of them…

There is the Help
There is the User Guide
There are the Level 1 and 2 Training manuals
There is the Rhino Wiki

…plus other pages for scripting and developers

@scottd @KelvinC - just noticed that the link on the main site to the user guide points to the V5 version, not the V6 version…

@davidcockey
A section for Polar coordinates has been added.
http://docs.mcneel.com/rhino/6/help/en-us/index.htm#user_interface/accurate_modeling.htm#Polar_coordinates

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Impressive!

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These three links on the support page are fixed, thanks.

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The 2nd item is a Rhino for Mac page - not sure which version though.
the 3rd, 4th and 5th items are Rhino V5 guides

The last two appear to be basically the same information, but one is in the Help, and the other is in the User guide.

I don’t know what the others are, but I don’t like it …
This seems to be the main site http://docs.mcneel.com/rhino/6/help/en-us/index.htm however I can hardly find it through Google search.