Nose Cone Help

[design-engine]

Yes... the four part boundary in Pro/SURFACE as apposed to the ISDX four part boundary. For the above example I would try to do the surface without using internal curve structure first to see how she looks then if needed add side curves.

 

[zpaolo]

Chris, this latest pic was done with the other method, not the "toupe" one.



The VSS of the body is a little longer, lacking only the tip, the tip is made in two halfs, surface constraints are important: normal to the plane and curvature continuous with the surface.

the other half of the nose is curvature continuous on both sides. Looks good IMO...

 

[Jacoolo]

I am not sure if curvature transition is required here. I suppose tangent is enough.

BB with curvature transition is however a good way to obtain boundry curves rather then using curve through points.

 

[Arbiter]

Hey Folks,
Thank you very much for the advice so far, I have had a chance to mess around tonight with the nose cone on my fuselage. I tried VSS and had no luck getting the geometry to even form when I clicked the two profiles, however, I did have better luck with the boundary blend, but with lack luster results (As Design Engine pointed out I was likely to have ). I am posting here what I did in PDF, and the file (I am using WF 4.0 Student). If anyone would be willing to hold a noobs hand through this I would greatly appreciate it. I am trying to create the nose cone so it's tangent to the last section of the VSS and normal to the centerline plane around the entire cone. Any thoughts/ step by steps I am missing. Everyone has been really helpful so far in getting me to think about this problem, I just need to learn some more. I am trying to get a book on Pro/Surface soon, so that should help give me a map to see how big the continent is so to speak. Thanks!

-Chris

2008-12-23_202050_Nose_Cone_Creation.zip2008-12-23_202101_00001_fuselage_trial.prt.zip

 

[Zaki]

Cant get the results in Pro, but in Catia. In surface modeling, Catia come from heaven.

 

[Zaki]

[No message]

 

[Arbiter]

It looks good, but unfortunately it doesn't help me , I don't have access to Catia . Thanks though, and Merry Christmas!

-Chris

 

[zpaolo]

Arbiter, if you use the traditional method I think the trick is to keep the "nose" as small as possible, I'll try to explain with a step by step mini-tutorial...

1) I start with a sketch of the side view, nothing difficult here



2) Then on the top plane I draw half the profile, forcing the spline tangency at the tip




3) I mirror the side profile and create a datum plane, DTM1, which will help me in defining the main VSS...



4) Now for the main fuselage, I define a VSS using portions of the main curves, I trim the end of the curves at DTM1, and define the VSS as constant normal direction, normal to DTM1. the VSS should look as follows:



Notice that curves end at the front plane, leaving room for the tip

5) Now for the tip I use boundary blends selecting for the first direction curve 1 (the tip's profile, be sure to trim the curve correctly at the DTM1 plane) and 2 (the VSS side), surface is normal at edge 1 and curvature continuous at edge 2.

I then add the second direction curve, that is the profile, trimmed to DTM1 and "free", to guide the shape of the tip. This is not needed if the tip is small enough you won't see much difference



6) To "close" the tip you need another boundary blend, be sure to select the curve attached to the VSS and the curve attached to the previous boundary blend. this way you'll have only to set curvature continuity for both edges. Then add the side curves as before.

The result will look like this, it's absolutely smooth... I tried with different profiles and curves, and as I said, the model failed more often when keeping a "long" nose from the VSS. Try to extend the VSS as further as possible...



PS: I'm sorry but I cannot open the part file 'cause I'm not on WF Student Edition

 

[Arbiter]

Zpaolo,
Thank you very much for the mini-tutorial! I will give this a shot within the next couple of days! If I have multiple sections defined and I want to create the boundary curves you have based on them, would it be good to use datum points or just points? The idea would be to make the lines like you have driven off of the sections I define at specific points along the length, and once I am done, I have the nosecone to make from these curves. Is that possible with this technique? Thanks again and Happy Holidays!

-Chris

 

[design-engine]

it is better to use less edit points when using a spline FYI.Instead use a line on both ends and control tangency to get to form. Makes the curve more simplistic.

 

[Arbiter]

Bart,
Can you elaborate by what you meant in your last post? particularly, I do not understand what you mean by using a line on both ends... Thanks!

-Chris

 

[zpaolo]

Chris, it looks like you have to model your part through cross sections instead of contour lines, in that case it'll be probably better to use the swept blend tool, or a combination of boundary blend curves...

 

[Arbiter]

Zpaolo,
That is correct, I would like to control the cross-sections of the body at different axial stations along the fuselage. Right now I am still having trouble making the nose cone blend well. I will work on it some more in the next few days and post my progress. In the meantime if anyone would like to demonstrate the toupee method for creating 4 curves from 3 so that the continuity is maintained that would be most awesome! Thank you all for your advice so far, I feel I am getting closer, and gaining more understanding! Take care, and Merry Xmas!

-Chris

 

[design-engine]

do this as an experiment In sketcher draw a spline but only dig the screen twice.Any line between two points is a strait line. Now draw two lines (not a spline) at either end of the spline and force tangent both lines to the spline. Now turn those lines to construction entities. Be sure to brake any Horizontal or Vertical constraints to either construction line/curve.Now modify those lines and notice the spline modify. That spline in alias studio is called a single span curve because their are no internal edit points making the curve complexity increase to a multi span curve.

 

[zpaolo]

do this as an experiment In sketcher draw a spline but only dig the screen twice.Any line between two points is a strait line. Now draw two lines (not a spline) at either end of the spline and force tangent both lines to the spline. Now turn those lines to construction entities.

I saw this trick of yours in one of your videos I played a little with WF 5.0 and all this tweaking of splines in sketches (and also the nose of my previous example) works interactively with "dinamic edit", quite impessive I must say...

 

[design-engine]

for those interested in keeping up with what design engine is up too.


Design engine has created several new surfacing workshops (and other classes) for 2009...These are in rough draft form but thought i could get some feedback from you guys. "Some of these classes are designed to differentiate from the PTC CERTIFIED classes we will be offering in 2009. Who knows... maybe ill start using Powerpoint at the conferences like the resellers. <slam>

[url]http://www.proetools.com/courses/pro_surface/level8surfacedi t.htm[/url] < Designing Products with Surface Edit functionality in WF4.0 ISDX

http://www.proetools.com/courses/pro_surface/level9.htm < Surfacing Air Forms with Pro/ENGINEER

http://www.proetools.com/courses/rhino/level5.htm < yacht design workshop for the rhino dorks.

http://www.proetools.com/courses/rhino/level6.htm < Jewelry Design workshop (to get your mom out of the house.

I have a similar disdain for Rhino like I have for solidworks.

http://www.proetools.com/courses/zbrush/zbrush1.htm < zbrush is used to paint and texture geometry then export back out to maya. mostly used for game design and special effects on movies.

http://www.proetools.com/courses/adobe/premire.htm < professional video editing software

http://www.proetools.com/courses/adobe/afterreffects.htm < special effects that can be applied to your video edits

http://www.proetools.com/courses/adobe/afterreffects.htm < your basic web design class using dreamweaver

http://www.proetools.com/courses/adobe/flashactionscript.htm < flash action script class now added to couple the Flash class we have offered for years.


Here is a quick one for you. I had a conversation with a PTC hi-up sales guy. He told me that i have angered some of the PTC resellers across the country. My response... "that is nothing... be glad your not a solidworks reseller." "They hate me more"
Edited by: design-engine

 

[rmatija]

srry wrog post
Edited by: rmatija

 

[puppet]

Lol @ Bart


"My response... "that is nothing... be glad your not a solidworks reseller." "They hate me more than anyone else." "


Your one of the greats Bart only makes me wish i was in the usa to shout u a round of beers

 

[jeff4136]

I guess I've seen about a hundred discussions like this one
over the last ten years. They always, each being a carbon copy
of previous versions with new participants, plateau and stagnate
about this point.


It's almost a new year. Let's break the mold, do some things
differently and get past it.


Low end techniques, e.g. using functions and methods that have
been available in 'CAD for the masses' for well over ten years
(actually Autodesk purchased MES code with some relatively
'advanced' functions in '92 but never really developed on it
because ACIS, which they'd licensed in '90 and subsequently gave
a bad name ... but I digress, development made it redundant),
don't work any better now than they did ten years ago. They
don't work any better in high end CAD than they do in low end
CAD and, with few exceptions, don't work better in brand X than
they do in brand Y.


Pretty pictures and videos can be informative or they can be ...

... misleading. No one knows which until the geometry is analysed
and understood (which also requires a bit of skill and practice).


Can Student Edition import / export model geometry? It would be
more conducive to learning if everyone wasn't dreaming up their
own variations of 'curvy' reference geometry sets and goals.
2008-12-27_062942_prt0001_iges.zip



IMO anyone that's serious about this sorta stuff would do well to
back off and spend some time studying simpler shapes and their
definitions. Start with conics, work thru beziers and graduate to
b-splines. Anyone that's not serious should just leave it be.
Casual interest won't get any further than the hundred or so
discussions that have gone before, plateaued and gone stagnant.


Bart should do a demonstration model for this one and improve
Design Engine's signal to noise ratio a little. Thirty, or so,
minutes well spent.

 

[solidworm]

it's really interesting how you do everything with VSS and use your brain to construct G2 connections instead of the software.can you please upload the WF2 part?
Thanks.

Edited by: solidworm