control problems

[Martugino]

save to all I have the 2012 version of autocad, my problem is that I often have to draw nets of 3d tubes, with previous versions I drew a polyline of percose (path or trajectory of extrusion) and to one of the estermes two concentric circles, I then extruded the circles along the trajectory and below with the command you will subtract the two cylinders to obtain the tube. with the version of autocad 2012 the subterranean command no longer removes the inner area of the exterior so I always see two concentric cylinders. I would like to understand if I misset a design variable or if I am wrong procedure.

 

[GP.]

There are no special variables to set, but I'm allowed to recommend another procedure.
- draw the two circles where you want, without aligning them to the path of polylinese
- creates a region between the two circles, corresponding to the thickness of the pipe
- swept command, as objects select the region and as path the polylinea

if you create the regions of the various diameters you use, with delobj = 0 draw them once and do not need to align them each time to the path.

 

[Martugino]

Thank you gp for your intervention, I have performed the operations as you have advised me however, maybe I did wrong something, but the result is that of the annex so it does not erase the inner part of the region.

 

[GP.]

have you created the perforated region?

 

[Cristallo]

in wireframe mode, you will always see both the outer circle and the inside, even if it is really a hollow tube (the tube is bounded inside and out by 2 circles...).
try to see in conceptual or realistic mode. If you perceive the hole then you will understand better.