Monday, February 18, 2013

Missing lines linework when plotting hidden lines in autocad Automatically set setvar Hideprecision and DispSilh every time you start AutoCAD

Missing lines when plotting in autocad



Missing linework when plotting with "Legacy hidden" shade plot mode

Issue

You have plotted using the "Legacy hidden" shade plot mode and you notice linework is missing from the final output. Hidden line removal missing lines

Solution

This is likely the result of the HIDEPRECISION system variable being set to 0.
HIDEPRECISION = 0
HIDEPRECISION = 1

HIDEPRECISION controls the accuracy of hides and shades by controlling whether hides are calculated in double precision or single precision. With HIDEPRECISION set to 1, hides are more accurate because they use double precision however it also uses more memory and can affect performance, especially when hiding solids.
The default setting for HIDEPRECISION is always 0. This setting uses single precision calculations and less memory however the lower accuracy can also mean hiding linework that should not be hidden.
If you are encountering issues with the "Legacy hidden" shade plot mode - this can also be seen when using the HIDE command - make sure that HIDEPRECISION is set to 1 before plotting.
Note: The HIDEPRECISION system variable setting is not saved and will not persist beyond the current active session. Each time you stop and restart AutoCAD, it will reset to the default value of 0. If you want HIDEPRECISION to always be set to 1 you should add a bit of AutoLISP to your ACAD20xx.LSP file to set this at run time. For example:
(setvar "HIDEPRECISION" 1)