Making solid extrusions using lines and arcs

[Ron Kenyeri]

Just started a new project and I was determined to use the 3-D commands in VW to simplify the view layouts.

I started by laying out the main solid by creating its profile by placing the critical shafts and then using the line command and developing the rest of the profile using the tangent command.

Got the profile done in 3 minutes! Now I want to extrude the profile.... Well the the remaining arcs are solids, the lines seem to be nothing but surfaces! So my questions are:

1. Is it possible to make a solids profile using 2-D lines & arcs commands in VW?

2. If not is there a command that will take my 2-D lines & arcs into some thing that can be extruded?

2a. I tried convert to polyline - nogood

2b. I tried convert to nurbs - no good

2c. I tried convert to curves - no good

If the answer is - make a rect, extrude and then cut the rest away, then I will again not be using 3-D since I can never get any of the tangent commands to work with an extruded circle. And I do not want to spend all day calculating tangent locations to manually enter point locations on a 3-D polyline. Thats why I have a computer.

Now if the answer is - make your 2-D profile and click X, Then does anyone have a GOOD 3-D tutorial!!!!

Thanks,

Ron

[Biplab]

You can use the Tool-->Compose command to connect up lines and arcs into a single polyline - and extrude that.

[Ray Libby]

Select all the objects and use tool : compose. You can then extrude the object.

BTW, I do some work in Franklin Park.

[Ron Kenyeri]

Thanks,

I new I was missing something. I have looked thru the power pack manuals and tutorials, and they never show this method.

In progressive die/machine design, most projects start from a piece part, And they are never nice simple box/cylinder parts. It would be nice to see a "real world" example in one of the tutorials, showing how the tools in VW can be used build a progressive die/machine from the ground up.

Well that is my two cents,

Ron

p.s. Ray are you a mechanial engineer?

[propstuff]

Ron,

Note that the compose tool only works if the end points of the various lines etc are EXACTLY coincident.

I've had Compose fail on NUMEROUS occasions even though the SmartCursor snaps have indicated that the end (of an arc, for instance) has been snapped to.

On numerous occasions I've had to force points to be coincident with Parametric constraints. What a PITA!

This can be improved by reducing the snap radius in the preferences. Making the2D conversion Very High also seems to help. (why?)

The next thing is: using the Combine/Connect tool to join segments helps a lot. It can't close a polyline though, and the final Closing needs to be done with the Compose tool.

Of course; when composing arcs and circles into polys, they lose their "circle" behavior, i.e centres and radius, dimensioning, editability.

I usually place a locus at the centre of arcs before composing, and replace it with a 3D locus grouped together with the object after extruding, and, also: save a grouped duplicate of the objects(and centres)to a "parking" layer prior to composing into the poly for extrusion.

This leaves maximum options for editing (eg changing the fillet radius between two crank arms) later on, with out having to reconstruct too much.

cheers,

N.

[ 05-09-2004, 06:11 AM: Message edited by: propstuff ]

[Ron Kenyeri]

Nickolas,

That is very true, the first few times I tried that I got the similar errors. It seems that the tangent command does not "work". If you take the end of a line, and start a line from that end, and go tangent to a circle everything seems ok. But once you trim the circle, it simply dissapears, so first you have to place some ref lines, trim the circle, and then go back and combine the arc to the line and then compose the profile to get a valid solid.

I spent a lot of time this weekend learning how to get things right.

Maybe I should put all of my notes together and make a manual!

Thanks,

Ron