Civil 3D – South African Country Kit

The South African Civil 3D Country Kit may be downloaded from this address (a PDF document is also available for download here):

https://knowledge.autodesk.com/support/autocad-civil-3d/downloads/caas/downloads/content/civil-3d-country-kits-for-south-africa.html

It is a Zip file that contains an html file as well as some .CAB files in a separate directory. Installations instructions are easy to follow.

After installation the Autodesk RSA template is available for users. Y is defined vertically up on the computer screen, while X is defined to the right (Z/“elevation” out of the screen). North is rotated with respect to the Y axis by 180 degrees.

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Some Civil 3D commands use only the World UCS as a reference. For instance, the transparent line subcommand, Bearing Distance (on the Transparent Commands toolbar), only references itself to World UCS. That means, regardless how true north is aligned to the World UCS, the bearing and distance will only have meaning with respect to the World UCS. While it does not preclude one from using the transparent functionality Civil 3D provides, case must be taken when using them, because they will lose their meaning if referenced to true north, as represented by the compass of the view cube.

To complicate matters further, survey coordinates in South Africa is defined with Y oriented to West and X to the South, (Z/“elevation” into the screen). Autodesk provides tools to handle the coordinate transforms. They reflect the coordinates about the line x=y (“X becomes Y and Y becomes X”). These tools include labels and point import/export styles. Not only are the coordinates transformed, but the coordinate reporting convention for South Africa is (Y, X, Z). The only way in which there can be a true mathematical alignment of survey and program coordinate systems is if elevation is defined in the positive z-direction. Since this is impossible with the South African definition (right hand rule) a person using Civil 3D must make accommodation that the program cannot reflect SA definitions exactly. The SA definition would have to be changed for them to align.

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Note: the template view cube is set to align itself to the UCS. This can be set in the view cube properties.

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