How to create and modify a parametric object ?
Two differents ways exist to create parametric objects: the RhinoParametrics command mode, which uses the creation commands in the RhinoParametrics panel, and the Rhino command mode, where standard Rhino commands are interpreted by RhinoParametrics.
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RhinoParametrics commands are accessible from the tool box in the upper RhinoParametrics panel. The icons found here are identical to the corresponding Rhino command icons. |
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The creation parameters of each object type are either numerical value fields (the x,y and z point coordinates for example ) and / or references to other parametric objects in the current project. For exmaple, consider a point on a curve: its defining parameters are the supporting curve, the reference point and the curvilinear abscissa.
The point is added to the project tree and can be edited/modified by right-clicking on the node to open the contextual menu, and selecting Definition option.
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The object's parameters can now be modified by:
- Changing a numerical value.
- Changing the reference to another object, for example the end point of a line segment, is done by clicking the selection field, which prompts for a new selection by displaying "Select...". Then select another object. The selection can be made in the tree or directly or in the 3D view.
In the example below, we modify the x,y,z coordinates of a line segment' ends; this modification is propagated through the model and triggers the updating of all the objects which reference this line segment.
In this mode, RhinoParametrics intercepts and interprets Rhino commands. When the user creates an object with standard Rhino commands, RhinoParametrics tries to build a parametric object by analysing the geometry created by Rhino. Whatever the analysis' result (success or failure), the initial Rhino geometry is deleted. If RhinoParametrics doesn't succeed in creating a parametric objet, a message is displayed offering to create a link to the non-parametric object. This message will apppear only if RhinoParametrics is active. To desactivate RhinoParametrics, use the  button .
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The dynamic creation of parametric objects (e.g. using Rhino commands) is a simple, intuitive approach. RhinoParametrics interprets the object created using Rhino commands, and attempts to derived Iits defining parameters. Of course, ther are instances when these parameters cannot be identified correctly, or even be found. In this case, no parametric object is created. |
The limits of this process are described elsewhere. If RhinoParametrics cannot create a parametric object thus, the user can of course resort to the appropriate RhinoParametrics commands. Note: while using Rhino commands, if a point is being created RhinoParametrics will attept to use existing points before actually creating a new one.
All RhinoParametrics commands have a "Rhino command" mode. But not all Rhino commands are interpreted by RhinoParametrics. For example, Rhino's Ellipsoïd command will not generate a node in the Tree, as RhinoParametrics cannot create a parametric object from a Rhino Ellipsoid.
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In order to improve ergonomy and user friendliness, a message is systematicaly displayed when the user creates an object that cannot be interpreted by RhinoParametrics. As an option, the user is offered to create a "link" object to the Rhino object, which may be used later on in the process of RP parametrisation.
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