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simple modeling question


dumfatnhappy

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wish I had a pic to post but here goes.

 

I want cylinder shaped like a birthday cake, then I want to invert a cone (point side down) into the top about halfway down (not quite all the way to the edge). I can't subtract that cone part from the top of the 'cake' for aome reason. I could do iall this with faces but I want it as a SOLID so I can shove a paper towel tube through it (and subtract it)

 

does this make sense to anyone? :?

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so basically you're drawing the bottom of a wine bottle, but having constructed a cylinder and a cone, you can't subtract the cone from the cylinder?

 

is this because you don't know how to do it or because your AutoCAD is being stroppy about the procedure?

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so basically you're drawing the bottom of a wine bottle, but having constructed a cylinder and a cone, you can't subtract the cone from the cylinder?

 

is this because you don't know how to do it or because your AutoCAD is being stroppy about the procedure?

 

I used the "cone" command from the 'massing' palette and I assumed it was a 'solid' but still unsure, (it won't let me subtract from the cylinder) also it will not construct inverted (has to have a "positive value" for the height at which point I have to turn it upside down). I'm very new to solids.....grew up on 3Dfaces.

 

bottom line is I don't know how :? , can you help?

 

thanks,

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in theory you should be able to apply Boolean algebra to both those items

 

sorry - I've not done this since R14!

 

what is it you're drawing btw? does this go with the rail you were drawing on another thread?

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yes it does, it's a Fly-Ash unloading station for rail cars. 3 new storage Silo's (115' tall 50 ft. in dia.). I'm trying to show the stuctural 'layers' of concrete with an 8' diameter tunnel going through the bottom (i.e. paper towel tube) As hard to explain as it is to model I'm afraid....

 

Funny thing is, the client was so impressed with my first model (attempt) they want me to do another site for marketing purposes. Now I need to learn rendering ..... uhg! not enough hours in the day.. (starting to affect my golf game even...) ;-)

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Here's an option: I'm not sure about constructing a cone being a solid - but rather than a cone how about just using the taper option when you extrude a circle? That should get you what you want.

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wish I had a pic to post but here goes.

 

I want cylinder shaped like a birthday cake, then I want to invert a cone (point side down) into the top about halfway down (not quite all the way to the edge). I can't subtract that cone part from the top of the 'cake' for aome reason. I could do iall this with faces but I want it as a SOLID so I can shove a paper towel tube through it (and subtract it)

 

does this make sense to anyone? :?

 

I have Mech 2009 and just made a cylinder and a cone and was able to subtract the cone from the cylinder. Are you getting any error messages? Or is it working and you just can't tell that it worked?

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I make the cylinder.....then the cone (still have to give a positive number for height) so I flip the cone upside down.... then try to subtract and it doesn't even recognize the cylinder as a solid.

 

I'm tired (and over it for tonight) will readdress in the morning. Thanks rkent, I may have some other 09 issues to discuss with you if you don't mind.

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You say Autocad doesn't recognize the cylinder as a solid? What does it say in the Properties palette when you select it? If it's not a solid then you won't be able to Subtract anything from it.

 

Maybe you should post the file here for us to take a look at? :unsure:

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I tried but had issues (too big (you're kidding right?). then tried a screen shot but still no joy. I think the revolve command will do it. I'll get back to you though.

 

thanks for your help Cad64

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I make the cylinder.....then the cone (still have to give a positive number for height) so I flip the cone upside down.... then try to subtract and it doesn't even recognize the cylinder as a solid.

 

I'm tired (and over it for tonight) will readdress in the morning. Thanks rkent, I may have some other 09 issues to discuss with you if you don't mind.

 

How are you flipping it? I can grip the top and pull in the opposite direction. Also you could rotate the UCS so the positive direction for the cone is going in the direction you desire.

 

You still haven't told us if you are getting any error messages or messages in general when you go through the subtract command.

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I pick the cylinder and when I hit 'enter' it says "No solids or regions selected" I believe the revolve command is what I want. I'll try it later when I'm on that project and get back to you. I rotate it by making my UCS 'Left' and then rotate it 180.

 

Thanks,

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