Corner Round Blend Surface Challenge

[jsantangelo]

I was cruising the internets last night and I came across a post on the T-splines forum showing how to do a Fillet of 3 intersecting cylinders with T-Splines. I started to create the same thing in Pro/e. I think I set-up all the REF surfaces and curves correctly. I broke it down to 4 sided surfaces. Here is how I did it:
<a href="http://www.screencast.com/t/v7PVncVdvi0" target="_blank">
</a><div style="text-align: center;"><a href="http://www.screencast.com/t/v7PVncVdvi0" target="_blank">Part 1

http://www.screencast.com/t/v7PVncVdvi0</a>



<a href="http://www.screencast.com/t/7HvLFsShF" target="_blank">Part 2

http://www.screencast.com/t/7HvLFsShF</a>

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As you can see in the video when I try to do a boundary blend with tangent and normal end conditions or tangent-tangent I get an error saying:

<div style="text-align: center;">Bounding curve(s) are not tangent to tangent surface at highlighted point(s).Recommended actions: Relieve tangency conditions or redefine the curve.

<div style="text-align: left;">I tried a bunch of other ways to try to make this surface (VSS, a swept blend). Any hints or tips? Am I over constraining it? Also no ISDX please (since I don't have it) therefore making it a challenge

Cheers!
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[dgs]

I noticed in your transition sketch, you have constrained the one end of the spline as tangent to a vertical construction line. Try re-ordering the sketch to after the larger dia. extrudes. Then create an intersected curve between the sketch plane for the spline sketch and the large dia/ extrude. THEN, make your sketched spline tangent to that interescted curve.

You should do the same with the small dia. extrudes as well.

I've found that sometimes, although the geometry is created to have the tangency desired, if there's not a direct path between the two items, Pro|E can't determine the tangency.

 

[jsantangelo]

I noticed in your transition sketch, you have constrained the one end of the spline as tangent to a vertical construction line. Try re-ordering the sketch to after the larger dia. extrudes. Then create an intersected curve between the sketch plane for the spline sketch and the large dia/ extrude. THEN, make your sketched spline tangent to that intersected curve.

Thanks for the input. Now do you mean the one called REF_CURVE in the Model Tree? I didn't show it in the video but what I did for one end was use "X Sec" in the Sketcher References. Wouldn't that be the same as creating an intersection curve?

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Also since I only used REF_CURVE to locate the center point for the Datum Curves I created, does it really affect them?

 

[dgs]

Yeah, ref curve is what I was talking about.I thought it was the curve that defined the boundary blend edges.

The curves that do define those edges got cut off at the end of the first video, adn I didn't watch the second until now.

What happens if you don't try to apply any tangency or normal conditions to those transition curves?

 

[design-engine]

you can do that round with Pro/E Round tool as well.

 

[dgs]

Bart - Are you sure? Take a look at his videos, I'm not sure that you could create that using the round tool. If so, I'd like to see it!

 

[jsantangelo]

Yeah, ref curve is what I was talking about.I thought it was the curve that defined the boundary blend edges.

The curves that do define those edges got cut off at the end of the first video, adn I didn't watch the second until now.

What happens if you don't try to apply any tangency or normal conditions to those transition curves?

The REF_CURVE was to establish the Instersection point for all 3 Datum curves.

Ugg and Lee show up to the party...

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Would the "Add side curve influence" or "Add inner edge tangency" be beneficial in the BB? I've tried multiple combinations and none seem to help.

I've attached the part file. It is in WF4 format.

2009-05-21_154104_WF4_impossible_corner.prt.zip




Edited by: jsantangelo

 

[dgs]

What I was thinking is that you create BB #1 tangent to the two cylinders, but free on the opposite edges. Then, create BB#2 tangent to the two cylinders and to BB#1. Keep going with tangency where there's a surface available, free where there is not.

I'm thinking that perpendicularity through that transition isn't necessary.

 

[jsantangelo]

What I was thinking is that you create BB #1 tangent to the two cylinders, but free on the opposite edges. Then, create BB#2 tangent to the two cylinders and to BB#1. Keep going with tangency where there's a surface available, free where there is not.

I'm thinking that perpendicularity through that transition isn't necessary.

Even with that combo, the Reflection analysis shows breakage from one BB to the mirror.

 

[dgs]

No, I'm not thinking to mirror anything. In your image above, instead of a BB and a mirror, create 2 BBs, the second constrained tangent to the first.

 

[jsantangelo]

No, I'm not thinking to mirror anything. In your image above, instead of a BB and a mirror, create 2 BBs, the second constrained tangent to the first.

No joy. With 3 tangent constraints and one Free it won't build a surface. I've attached the WF4 part file in the above post. The error again is at the point where all 3 datum curves intersect.

Edited by: jsantangelo

 

[mgnt8]

Have you tried VSS? There is a way to create a surface with the singularity in the center provided the outside boundaries are all tangent. It's been demonstrated before in one of Jeff4136's posts.

Can you add tangency conditions to the outside trajectories?

I just did it with the curves you have now, but am yet unable to establish tangencies with the cylinders. It seems like there has got to be way to do this. I'll try to mess around with some of his equations to see if I can force something in. If I had more time I might be able to get it but vacation is looming



Edited by: mgnt8

 

[jsantangelo]

Have you tried VSS? There is a way to create a surface with the singularity in the center provided the outside boundaries are all tangent. It's been demonstrated before in one of Jeff4136's posts.

Can you add tangency conditions to the outside trajectories?

I just did it with the curves you have now, but am yet unable to establish tangencies with the cylinders. It seems like there has got to be way to do this. I'll try to mess around with some of his equations to see if I can force something in. If I had more time I might be able to get it but vacation is looming

Can you upload the file to see how you set up the VSS?

 

[jsantangelo]

So I used an N-sided Surface and it created a surface close to what I am shooting for. The curves I created were close. In this pic the blue lines are the curves I created and the red are the curves in the n-sided surface. I still want to figure out how to do this with BB or VSS though

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[design-engine]

try the new n-sided surface in WF5.0 it actually trims back all in the script.

The n-sided surface tool in Pro/SURFACE is not the way to go when building this surface... although it sure looks good there... impressive.
Edited by: design-engine

 

[dgs]

I'd love to see how the N-sided surf works. I've tried to use it, but the selection prompts are useless. I have no idea what to select, so I gave up. I guess I could look it up in the help files ... (I may have, those aren't always 'help'full.

)

If I get some time, I'll download your model and try it.

 

[zpaolo]

As far as I can see the problem is that you build three curves and then use 6 "segments" from them, but each segment has not the correct tangency to the surface you build with the first BB... I'd try instead of making 3 curves, to make 6 curves all converging to the center point, where you'll place a plane normal to the already present axis, and force tangency of each end of the 6 curves to the surface of that plane.

Or maybe it will not work and I'm sayng silly things

 

[design-engine]

There are three types of modelers out there in our world. History lesson.... and its hard to type I crashed hard on the skate board last night and am feeling it in the wrist that broke my fall.

We teach t-splines in maya and rhino and that algorithm was first developed in the early 80's however the computers were always too slow to develop the shapes.

1 surface molders (proe fits under this category as a parametric solid modeler - a very specific type of surface modeler like a square is a very specific type of a rectangle)

2 polygon modeler or mesh model - dxf, points, polygons and triangulation files fit under this category

3 sub divisional model < t-splines and sub'd are relatively the same.

programs like Maya do all three types of models. While the traditional Solid modelers have not always done but the two. importing a triangulation and solidifying it is considered the top two. It has been shown at the 2008 PTC WORLD conference that WF6.0 may have T-Spline modeler which is way cool by the way especially if PTC can incorporate draft functionality too which is the hard part. We teach that in Maya BTW... since design-engine is focused on product design as opposed to character modeling like most Maya schools....

Although we teach rhino our instructors hate me because i have so much more experience than they... and proe can run circles around their ID models. First we can model in the same amount of time, but proe can modify the model in seconds and prove form better than in rhino.

My quote from last year: "its not how fast you model something but how fast you modify it 20 times"
Edited by: design-engine

 

[zpaolo]

I'd try instead of making 3 curves, to make 6 curves all converging to the center point, where you'll place a plane normal to the already present axis, and force tangency of each end of the 6 curves to the surface of that plane.

It worked, with 6 curves with surface tangency to the cilinders and to the center plane, BBs with tangency and normal to the other planes.

It can't be done curvature continuous, I think because the arcs are not CC with the straight portion of the cilinders (being that the curvature of the arc is constant and the side of the cilinder is, whell, not curved ).

I can post the part but it is WF5.0...



Edited by: zpaolo

 

[jsantangelo]

I'd try instead of making 3 curves, to make 6 curves all converging to the center point, where you'll place a plane normal to the already present axis, and force tangency of each end of the 6 curves to the surface of that plane.

It worked, with 6 curves with surface tangency to the cilinders and to the center plane, BBs with tangency and normal to the other planes.

It can't be done curvature continuous, I think because the arcs are not CC with the straight portion of the cilinders (being that the curvature of the arc is constant and the side of the cilinder is, whell, not curved ).

I can post the part but it is WF5.0...

Please do share. I have WF5 to tinker around with. Looks good!

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I just did what you recommended in WF4 and it worked. A star for you

, lol. All this trouble to setup a corner blend with so many features, yet in SW you could do it in one using the edges and even make it Curvature Continuous.

Hey Bart, do you know if/when Pro/e is getting a tool to like surface Surface Fill in SW?


Edited by: jsantangelo