D3PLOT 22.1

Further Notes on Volume Clipping

Further Notes on Volume Clipping

Note 1:

Clipping is calculated using the simple test: "is the element centre within the current volume?". Then either the whole element is displayed, or it is not drawn at all. No interpolation across elements takes place.

This can give an effect rather like taking bricks out of a wall as shown in this figure.

Note 2: Volume clipping does not work with stonewalls. This is because their geometry is at best strange, and often has infinite dimensions, making it too hard to implement.
Note 3:

On 3D devices the graphics mode will be switched temporarily back to 2D when creating "location" plots.

Note 4: You cannot screen-pick entities from "location" plots.
Note 5: When a clipping volume exists you will find that the CV (Current Volume) button is live in entity <list> entry panels. (See Selecting Entities for Operations , and its accompanying figure .) This provides the option of selecting entities within the current volume.
Note 6: Volume clipping can affect other parts of D3PLOT, as shown in the following table:


Function affected by clipping Relevant D3PLOT command Section
Averaging of element data at nodes AVERAGING... Clipping ignored switch
Calculation of free edges DISPLAY_OPTIONS
FREE_EDGES... CLIPPING -> EDGES
Exclusion of elements from a "scan" for maxima/minima WRITE SCAN