cannot subtract the heliex fromt the cylinder

[Anonymous]

hi everyone:

i am new to the Autocad, I have a question, i cannot subtract the heliex fromt the cylinder, in order to make you see my queston clearly, i have attached my file, please check the attachment. (please see the two red cylinder in the attachment) 

Thank you!

[Alfred.NESWADBA · Accepted solution]

Hi,

you helix-circle is a surface, not a solid, so erase your surface, start again command _EXTRUDE, make sure with option _MODE that the result of the command is a SOlid and then again select the circle as profile and the helix as path.

Good luck, - alfred -

[Anonymous]

Thank you so much, it is very helpful, I have solve the question, but can I please asl what is the difference between surface and solid in autocad? 

I have another questiion, I am working on the Jet Engineer and try to get rid of the the top and bottom surface so I have so the the propeller inside, then I check online that I can ise the "loft" to get ride of them, but it seems to me that it is not working, can you please help me? Thank you so much!!! You can check the attachment in the message. Thank you so much!!

[JDMather]

Are you a student?

Can you use Autodesk Inventor for this design rather than AutoCAD?