PDA

View Full Version : Swept Boss/Base Profiles



rwanttaja
05-27-2020, 12:00 PM
I'm trying to build a stand for a spaceship, where the stand itself inserts into one of the rockets and widens out to simulate a smoke trail.

Swept Boss/Base seems to be the way to do this, with a guide line to taper the object, but I keep having problems.

I understand how it's *supposed* to work...but am having a hard time getting it to work right. Here's a view of the sketches involved:

8447

If I do just the Profile and Path, I get a constant-diameter tube (as advertised). But when I try to bring in a guide line to taper the curved tube, I just can't get it to work reliably. In this particular case, it only builds the tube to the top of the short straight segments before the splines take off.

In other cases, I get weird alerts and it doesn't build at all.

Any advice? I've attached a ZIP file with a sample part.

Ron Wanttaja

cwilliamrose
05-27-2020, 05:20 PM
What happens if the path and the guide curve are each a single entity? What I'm suggesting is, as a test, make the second part of both a construction line and see if it behaves as you would expect.

Jeffrey Meyer
05-28-2020, 05:33 AM
May I suggest using a lofted "boss" instead of a swept "boss" - no guide curve necessary. Large circular profile at one end and small circular profile at the other. At the small end make the end condition normal to the profile to simulate the exhaust from the rocket. You can try making the large end normal also - choose the one that looks best for you.

Jeffrey Meyer
05-28-2020, 06:16 AM
Here's what the loft looks like using "normal to profile" at both ends:

cwilliamrose
05-28-2020, 07:24 AM
I wasn't able to open your file Ron but I played with it a little bit using your image to create similar geometry. I had a couple of theories, one was the lack of tangency between the two elements of the guide curve and the other was using two elements for the path a guide curves instead of one. The lack of guide curve tangency was not a problem -- it only made for an ugly part. The two entities making up the path and guide curve didn't turn out to be an issue either. For some reason the guide curve (either a single entity or two entities) was not accepted by SWx. When I first tried it I had drawn the circle first, then the path starting at the center of the circle, then the guide curve with its start point pierced by the circle - all in separate sketches. No joy. When I drew the curves first and then fitted the circle to them the sweep worked as expected. Why? I'm not sure but it may be that the start/end point of the circle coinciding with the start of the guide curve is somehow magic........

8450

rwanttaja
05-28-2020, 12:15 PM
Thanks much to those who replied...the Lofted Boss did the job nicely, and I didn't have to pound my head on the desk more than three or four times to get it to do what I wanted.

In addition to modeling WWI machine guns :-), I've been using Solidworks to make display stands for some of the memorabilia from my space engineering career. This stand is going to be used to display the Mission Patch from one of the programs where I was lead engineer...I'm trying to match the image on the patch. Here's a shot of what the completed display looks like, with the mission patch photoshopped in.
8452

I've already printed out the spacecraft, and am in the process of painting it.

A second program had a similar logo, but I'm quite a bit away from being able to model a realistic coonskin cap on the spaceship....

Thanks to all, again.....

Ron "It Really Is Rocket Science" Wanttaja

cwilliamrose
05-28-2020, 12:27 PM
That's pretty cool looking.....

CHICAGORANDY
05-28-2020, 01:21 PM
Buster Crabbe would be mighty proud says I.

rwanttaja
05-31-2020, 08:52 PM
Thanks again for the help. Posted a ZIP file to my web page with the Solidwork files for the ship and stand.

http://www.wanttaja.com/flash.zip
8457

Ron Wanttaja