Surfacing help

[Gemnoc]

I've always used SE for modeling metal profiles and sheetmetal.

I'm a little out of my depth here.

I'm trying to model a shape that's like a water drop (or an egg) cut in half.

How would I go about it?

I'm unable to make anything with a sweep. It tells me geometry is self-intersecting.

Am I wrong assuming that for a surface sweep, the path cannot touch both ends of a profile?

Solidworks' sweep feature seems more powerful. If you'll look at this spoon modeled in SW, the guide curve touches both ends of the path. Is there a way to accomplish this in SE?

Any help will be greatly appreciated!

BTW Matt Lombard's blog is really an interesting read. It's a pity he's on Solidworks!

 

[Gemnoc]

BC,

Thanks for the Intersection Point Command tip.

I've come back to this component and although your way is THE way to do this (it considerably better than the example I posted, with one almost smooth surface instead of 4 stitched ones), I still have some trouble with the point cross-section. It ends in a sunken area, like it's pinched.

See jpeg attachment.

I'm thinking of making my BlueSurf larger by offsetting my guide curves and points to the outside, afterward when I extrude my bean shape to the surface, the sunken points will be outside.

Any better ideas would be welcome.

Thanks!

And now to my 41st try on this BlueSurf!!! (yep, the last one was numbered BlueSurf 40)

 

[Gemnoc]

I'm not sure I was clear on my previous message.

See attachment showing the BlueSurf (along with cross section and guide curves) and the protrusion.

 

[beachcomber]

Hi Gemnoc,
After looking at your images, I came up with this solution that seems to give a pretty smoth surface.
I split the top-view profile into 2 then created 2 spline curves across from each end of the straight sides to an intersection point of the centre curve with a plane normal to each end of the straight sides.
Hope the image explains.

http://files.engineering.com/getfil...279-4a15-9587-46a0ed5a8bc1&file=Surface_2.jpg

bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.

 

[Gemnoc]

Hi beachcomber,

thanks for your help. You've spent some of your time to make this example, (and on a Sunday at that!) and I really appreciate it.

I've repeated what you did, but I want to be sure. Looking at my jpeg showing top view, have I done the path sections #1 & 2 right? Because if I make halves separated by the cross-section curve #2, the system doesn't accept them as they do not touch all the cross-sections. Making the intersection points doesn't seem to help. Also, the way I did it, I'm not sure either side of the BlueSurf is the exact mirror of the other.

Thanks again, and
Best regards,

Norm AKA Gemnoc

 

[Gemnoc]

You know, I just did the BlueSurf again without the path sections, and it looks the same to me...

 

[beachcomber]

Hi Gemnoc,
Have another look at my pic.
My path curve is a spline from the end of one straight side, to the centre curve, then to the end of the other straight side.
I'm away at work all week now but I'll re-create it and post the model - could be a couple of days though.


bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.

 

[Gemnoc]

Hi Beachcomber,

I figured as much after posting last night, but your jpeg says that the path curve is on a normal plane to the cross-section #1. Since the straight side is not parallel to the cross-section #2's plane, it would mean that at the other end, it's not normal anymore (refer to my jpeg). How do you manage that?

BTW after close inspection, the BlueSurf is indeed different if no path sections are used.

 

[beachcomber]

Hi Gemnoc,
As I posted last reply in wrong thread, here it is again.

bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.

 

[Gemnoc]

Hi BC,

Again, thanks for your help.

Last night, I found some interesting reading material from a search for "Solidworks surfacing". They are Powerpoint slides used for presentations at SolidWorks World. Although it is made for SWX, the basics are universal.

I thought it would be a good idea to post the link here for anyone interested in surface theory. I hope it is all right with the administrators.

http://www.dimontegroup.com/Tutorials/SolidWorks_Tutorials.htm

Look for the presentations named "Curvy Stuff", as well as "Surfacing for Blockheads". And as they request, please restrict downloading to outside business hours (Central time).

So far I've looked at intro of Curvy Stuff 101 and 102. It explains B-REP, analytic surfaces, the basics of loft.

This is something I would have expected to find in Solid Edge Help...