Show full version of the posting: Editable block

pweeks
22.11.2013, 22:21
Hey all,I currently work for a company that makes big commercial tanks for many different uses. The beginning part of making these tanks is really simple and similar to one another. Essentially it is just an cylindrical tank with an ellipsed head that extrudes half way farther than the total diameter of the tank. Then once the ellipsed head is made on both sides all the measurements that are left to be done is the length and thickness of the tank.I was wondering if I could somehow create a general sketch of what they look like and be able to link certain dimensions to all the particular measurements and it'll be able to stretch and extrude the drawing to all the inputted dimensions (whether it be in a dialog box or if the dimensions themselves are edited and change the drawing, similar to Inventor).I do realize this could probably be done very easily on other CAD programs but currently this is all this company has and is willing to spend right now :/. If there is not an easy way to do this or a possible way I guess I'll just have to try to advice my company to switch to a more efficient program for our needs. Any input is appreciated. Thanks

John Connor
23.11.2013, 12:46
Maybe it could be done using a dynamic block.  Are your tanks pretty much based on standard sizes (diameter)?  A lookup table could reference all the heads you typically use.

pweeks
26.11.2013, 18:22
Thanks for the response.I took a look at dynamic blocks yesterday. Never used them before, but yes that is the general approach I am going for. I think, for what I want to accomplish, I need to have constraints available to my AutoCAD, but unfortunately 2008 does not support this. I would use a look up table but we cover diameters anywhere from 3" to 20 ft. Seems like a lot to input for something that could possibly be editable by itself. I was able to create a block of the basic shape of the tank. I then attached some parameters with the stretch action to adjust the total length and height of the tank but I am unable to change the size of the head (ellipse). I keep hitting problems such as; the ellipse detaching from the entire tank, changing its size (linear parameter), and the ellipse doubling the total height of the tank (scale). As I stated before it needs to be half of what the total diameter (height) of what the tank is on a horizontal plane, when it is changing more of the vertical plane. (Not sure if all that is making sense but I tried to give my best description lol)Is there a way to be able to change the elliptical size without it detaching from the rest of the tank and just changing the horizontal length of the ellipse? 

John Connor
26.11.2013, 18:41
I suspected you'd have problems with the elliptical heads thus the reason for suggesting a lookup table.If you adjust the horizontal length don't you have to adjust the vertical height too?  Would seem to make sense.

pweeks
26.11.2013, 18:45
When it asked for items to stretch for the height I was able to select the ellipse and it is able to follow the rest of the tank. Like I said before it is just the horizontal measurement that needs to be changed now, on both sides of the tank.

John Connor
26.11.2013, 18:45
Take a look at this thread over at the AutoDesk Community re: stretch of ellipses.  It might prove of some use.http://forums.autodesk.com/t5/Dynamic-Blocks/Stretch-of-ellipses/td-p/1831752

pweeks
26.11.2013, 19:30
uploads/423875/TANKTEMP.dwgHmm... not quite. They are using a full ellipse and they don't really give a clear description on how they did it (as far as I could see, like I said still new to the whole dynamic block thing). I didn't realize I could attach files so I attached the file that I am working with right now. I am still doing research on the ellipses being stretchable but feel free to take a look and experiment with the parameters if you'd like.

John Connor
27.11.2013, 11:38
Did you download the dynamic block that was available?

pweeks
27.11.2013, 16:37
Yeah but from what I could tell they are not doing anything too different from what I am. When I attach the stretch points that they do, it just moves the entire ellipse rather than stretching it :/.

John Connor
27.11.2013, 22:33
I think trying to stretch an ellipse even if using a small straight segment between two halves is not going to give you the desired results.  More like an exercise in frustration.