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rhino:cplanecommand [2016/05/02] |
rhino:cplanecommand [2020/08/14] (current) |
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+ | ====== CPlane Command ====== | ||
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+ | > **Note:** //<color maroon> | ||
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+ | A CPlane (construction plane) is simply an imaginary plane that you do your drawing on. Since the monitor/ | ||
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+ | In Rhino, each viewport has its own construction plane. X is always horizontal and Y is always vertical. Z is always moving toward you (out of the monitor). Drawing commands usually use the construction plane coordinates when you draw but you can use world coordinates instead by using a " | ||
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+ | The **named views set cplanes** option is for those who don't want Rhino to have a different construction plane for each viewport. Most other CAD programs only have one construction plane set for the whole model so that option is for those who are used to that sort of thing. I kinda think having different construction planes for each viewport allows me to never think about construction planes or how to manage them so that's why I choose to not use that option. | ||
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+ | -Brian Perry | ||
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+ | ---- | ||
+ | As previously mentioned, a construction plane is simply a set of reference axes (X,Y,Z) which Rhino will follow when creating **certain** types of geometry (more later on that). | ||
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+ | Since Rhino allows you to work in multiple viewports (many programs don' | ||
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+ | It's a lot simpler, for example, in a program which only has one viewport visible at a time, like my CAM software. | ||
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+ | Personally, I use the **Named View sets CPlane** option in the 3 ortho viewports as well as using independent construction planes in the Perspective viewport (a lot of people work this way). I have a set of buttons which allow me to flip the construction plane around easily while working in the maximized perspective viewport, which I do most of the time. V3 even allows one to easily change construction planes in the middle of many commands. | ||
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+ | Note that the **Named View sets CPlane** option is only activated on initialization and when you reset your viewports (such as doing a 4View twice). | ||
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+ | Now, about when construction planes come into play... | ||
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+ | Planar geometry will by default be created on the active construction plane if you pick points (no Osnaps) or enter XY coordinates only. However, you can force Rhino to create geometry off the construction plane if you enter a Z coordinate, or Osnap to something off the construction plane. | ||
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+ | Other types of 3D geometry also use the construction plane as reference, such as things like a box or a sphere that use XYZ coordinates. | ||
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+ | Lastly, there are some types of transformation operations that use the active construction plane as a reference, notably Project and trimming with apparent intersections (including trimming a surface with some types of curves -- but watch out for planar curves, they act perpendicular to their principal plane and ignore the construction plane!). | ||
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+ | The World coordinate system, which is inherent and can't be altered, is simply based on the absolute 0 (world 0,0,0) of the file and follows the right hand rule. World Top means that the XY plane is parallel to the Top view, X to the left, Y up, Z coming out of your monitor (so to speak), and the origin at world 0. | ||
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+ | World Front is the same, except the XY plane is parallel to the Front viewport, etc. It can also be thought of as a 90 degree rotation of the World Top system about the X axis, looking down the axis from the X direction. | ||
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+ | There is also now a UPlane command (Universal CPlane), which allows the user to define a new "World Top Prime" construction plane, and Rhino will automatically create the other principal planes to match. | ||
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+ | --Mitch | ||
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+ | ---- | ||
+ | Some corrections and additions: | ||
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+ | First, project and trimming are not transformations. Transformations for [[rhino: | ||
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+ | The fact that Rhino treats planar geometry as if a construction plane is attached to it is one of the reasons that many people don't ever get involved with working with custom construction plane. For instance, if you revolve a planar curve 45 degrees you can then use commands like extrude and trim using the edge of the surface that is tilted 45 degrees without having to explicitly set the construction plane to that angle. And finally, the reason silhouette works relative to view is also a matter of definition. One would expect that silhouette be dependent on what you see as it is in the real world. | ||
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+ | -jim | ||
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+ | ---- | ||
+ | Silhouette is the only command that one can really use right now to get a theoretical partline on an irregular shaped object. I think we should have an option for it to act according to the construction plane or perhaps a different command for this purpose. | ||
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+ | --Mitch | ||
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