3D dished head on Tank

[irwin5338]

I am using AutoCAD 2012 and I noticed that the dish/dome command is gone. How do I make a dish? Any ideas or lisp routines?

[nestly]

I'm not aware that AutoCAD ever had a dish/dome command. I typically use 1/4th of an ellipse and REVOLVE for endcaps

[SLW210]

Used to be there. I wonder when those disappeared.

 

I believe it was just for surfaces or meshes.

[tzframpton]

Most people create a 3D tank in parts... do a Cylinder then try and add "caps". Since the entire tank is cylindrical I never understand why people don't just create half the profile with PLINE, then REVOLVE. This saves a lot of extra steps of then aligning and positioning the endcaps and joining them together.

[nestly]

I stand corrected, it is/was in AutoCAD2011

 

Command: 3D
Enter an option
[box/Cone/DIsh/DOme/Mesh/Pyramid/Sphere/Torus/Wedge]: *Cancel*
Command:

also... the command "_ai_dome" in AutoCAD2011 creates a Mesh dome... it's an unknown command in AutoCAD2012

Edited July 16, 2012 by nestly

[nestly]

Most people create a 3D tank in parts... do a Cylinder then try and add "caps". Since the entire tank is cylindrical I never understand why people don't just create half the profile with PLINE, then REVOLVE. This saves a lot of extra steps of then aligning and positioning the endcaps and joining them together.

 

I guess I'm one of the "most". Here's my reasoning:

 

I like to draw tank/pipe endcaps reasonably accurately, and they're not typically shaped as hemispheres, therefore a polyline arc segments aren't the best choice. Ellipses are a more accurate reprsentation, but you can't REVOLVE a ellipse directly into a Solid, so I do the endcaps, SURFSCULPT them into solids, then union them onto the tank body (cylinder)

[ReMark]

You might like the Buzzard's pressure vessel dished head lisp.

[tzframpton]

I guess I'm one of the "most". Here's my reasoning:

 

I like to draw tank/pipe endcaps reasonably accurately, and they're not typically shaped as hemispheres, therefore a polyline arc segments aren't the best choice. Ellipses are a more accurate reprsentation, but you can't REVOLVE a ellipse directly into a Solid, so I do the endcaps, SURFSCULPT them into solids, then union them onto the tank body (cylinder)

I agree 100% regarding a PLINE not being the best for endcaps, but I usually still use an ELLIPSE, do a little trimming, etc, then I can still perform a REVOLVE with the combined PLINE.

[SLW210]

Still there in 2011, looks like they did not put them on the ribbon.

 

I use PELLIPSE=1 then draw and trim the ellipse, then revolve to do an end cap. Been awhile, but now if the need arises I use Buzzard's LISP.

 

Of course if you need it to be a mesh, I guess Dish might work....

[tzframpton]

Buzzard's LISP still is the best option out of all our own methods, I do agree.

[ReMark]

Buzzard's lisp...don't leave home without it.