ginsu
Ginsu is an interactive slicing tool designed to be used with Geomview. It allows the user to move around a square slicing plane to an arbitrary position and then to slice a particular geom with that plane. Slicing involves dividing the geom into two seperate geoms at the plane of cleavage. Once slicing has been performed, each of the two new geoms created can be moved around and examined independently from the other. Ginsu runs only on Silicon Graphics machines.
Ginsu works by constantly querying geomview for the position of the plane as one moves it and then updating the internal plane equation it uses. The coefficients of this equation appear on the main panel for examination. When the plane has been properly positioned, one enters the name of the geom that one wishes to slice in the 'Target Clip Object' text window, then clicks on the 'Slice!' button. The old geom is then erased and replaced by two new geoms. The speed at which this occurs depends on your machine and the complexity of the geom.
In some cases one may want to manually enter the coefficients of the slicing plane. This can be accomplished by toggling on the 'Edit' button. Ginsu is now in edit mode and will no longer update the coefficients if the plane is moved about inside Geomview. To change coefficients now, one clicks in each coefficient text box and types in a new number followed by enter. The plane will be repositioned each time to match the new set of coefficients. Toggling the 'Edit' button off will put us back in interactive mode.
Some things to keep in mind: Ginsu turns normalization off when it is run and prevents it from being turned back on. This is because keeping normalization can have some unpleasant effects when cutting things. Ginsu depends on the clipping plane being present. If the clipping plane is somehow deleted, Ginsu is then forced to exit.
Sometimes color or normal information is lost when clipping certain geoms. This is because ginsu always converts a geom to an OFF format geom before clipping it. When clipping the "World" geom, everything in the world becomes consolidated into two geoms (this could actually be thought of as a feature).
Daeron Meyer email: daeron@geom.umn.edu The Geometry Center phone: (612) 626-8302 1300 South Second Street Minneapolis, MN 55454