help with Creo

[farren]

i have been playing with my Creo Cad, and while trying to rough draw a chimney i have become stuck. can some one explain how to do the base please.

 

[ChrisH-UK]

I'm assuming that's for a locomotive, wouldn't you need to specify what it connects to first? Or do you just want to extrude a flat "flange" and when you figure out what it's connecting to just get it to conform to that shape?

[rue_d_etropal]

If that is a lco chimney , then it is one of the more difficult items to start on. After nearly 5 years I have worked out how to do the flange at base.

For a start,you need the base to be cut to the shape of the smokebox. Then you need to build the flange based on that (complex) curve. From top view the flange is a circle, which means the radius along the centre line is less than that at right angles. In software I use, I found only way was to build p the chimey as a quarter section, with flange (filler) with a start and end radius.This was saved as a design component, and I used mirroring tools to build that up into a full chimney. OnceI ha worked it out, it actually made sense. I do find it does not always work( something in the internal calculations in the software), but it is a lot closer than I had got to before.

In fact I have gone one step further, to make it easier to add chimney to other parts of my designs, and create the base/flange as a separate item.

[Spitfire2865]

In solidworks, Ive managed it before with radiusing tools and then trimming back, but not sure if Creo would play the same way. It is quite the awkward shape.

[rue_d_etropal]

In software(Geomagic Alibre) I use, it is a fillet tool, which can either round off an edge or fill in along an edge. It also has ability to set radius of that fillet to a start and end value, which is needed to get the flange to sit properly.  Once I had discovered how it worked it was obvious and made sense. Standard engineering design tool, which is what I wouI hld expect in software designed for engineering.

I had been bodging it before, but the more I learn, the less I have to bodge, assuming my computer lets me do it. Some of these CAD tools are very heavy on memory to do some of the complex mathematics involved.

[Quarryscapes]

Not familiar with the software, but you could make a cylinder with inner diameter to represent the outside diameter of the smokebox, outer diameter to the radius of the base of the chimney base (doesn't have to be thick, just something there) Then intersect that cylinder with a cylinder perpendicular to it which acts as the diameter of the base of the chimney. That will give you a circle that has been bent around the smokebox. Throw in some guide rails between it and the rest of the chimney and you should be able to loft it. 

 

This is Fusion 360 but it illustrates the idea: 

 

[farren]

Thank you all for your suggestions I'll keep trying. Have got a couple of ideas to try tomorrow and if I get there I'll let you know.