What is the best way to create and hollow transition between these two extruded shapes?

[Rowboat]

 

I would like to create a hollow form that allows air to flow thru the circular shape and into/out of the trapezoidal shape.

 

Thanks in advance.

[VIRTUALENVIRONS]

There are a few ways, but if you post the file, it would be easier to demo.

[VIRTUALENVIRONS]

is this what you want to do?

 

 

 

 

[Rowboat]

1 hour ago, VIRTUALENVIRONS said:

is this what you want to do?

 

 

 

Yes, that is what I'm going for.

 

Here's a cleaned up file with the shapes from my picture and what it will eventually be a part of.

 

Thanks for your input here

Caddy vent.vwx

[VIRTUALENVIRONS]

Hi, need a little more info.  See short video below.

Are these two objects to be as they are, or centred, a distance, etc.

 

 

[Rowboat]

1 hour ago, VIRTUALENVIRONS said:

Hi, need a little more info.  See short video below.

Are these two objects to be as they are, or centred, a distance, etc.

 

 

 

 

 

They should be centered left to right, but the top of the circular object will need to be even with the top of the trapezoid.

As far as distance apart goes, they should not any farther apart than they need to be to make the transition happen.

 

The goal will be to mount a fan on the circular side to direct air in/out of the trapezoidal side.

 

Edited July 29, 2025 by Rowboat

[VIRTUALENVIRONS]

Enclosed is a file with a completed model.  On the second layer are two curves that can be lofted together if you need to shorten/lengthen distance.

If you need more help, just ask.

 

Do you need to know how this was done?

 

LOFT 2 .vwx

 

[Rowboat]

20 hours ago, VIRTUALENVIRONS said:

Enclosed is a file with a completed model.  On the second layer are two curves that can be lofted together if you need to shorten/lengthen distance.

If you need more help, just ask.

 

Do you need to know how this was done?

 

LOFT 2 .vwx

 

 

Yeah.

While I appreciate you spending time on this, I made this post asking how I could do this, not to have it done for me.

 

Also, there are no other objects in this file than what you have shown here.

 

 

Edited July 30, 2025 by Rowboat

[VIRTUALENVIRONS]

1 hour ago, Rowboat said:

While I appreciate you spending time on this, I made this post asking how I could do this, not to have it done for me.

 

Before I could do a tutorial explaining the process, I needed to know it was what you wanted, hence the model.  To get the curves required, there are several steps.

 

So, is this what you wanted?  

 

If so, I can do a short tutorial explaining the process.  

 

I just downloaded the file I uploaded and on Layer 5 are the two curves I used to make the joint.

 

 

[Rowboat]

20 minutes ago, VIRTUALENVIRONS said:

Before I could do a tutorial explaining the process, I needed to know it was what you wanted, hence the model.  To get the curves required, there are several steps.

 

So, is this what you wanted?  

 

If so, I can do a short tutorial explaining the process.  

 

I just downloaded the file I uploaded and on Layer 5 are the two curves I used to make the joint.

 

 

 

 

I feel like this would work for me, although the transition will also needs to have a thickness of .125" for it to be 3D printed.

I attempted an extrude on your drawing which did not work the way i had hoped.

[VIRTUALENVIRONS]

Have company today.  Will do tutorial tomorrow.  NURBS are different

[Rowboat]

Thank you so much for everything.

I do really appreciate it.

[Jeff Prince]

This can be accomplished using Loft in the 'no rail' mode, but there are many other ways too.

1st, extract the outlines of the inside form of the trapazoid, convert to a single nurbs curve.

next, break the circle into arcs representing 1/8ths, convert these to a singular curbs curve.  This is done so the circle has the same number of vertices as the trapezoid.

finally, use Loft/no rail mode and make a ruled solid.

 

Repeat the process of the outside surface.

 

Finally, subtract the inside from the outside and you have your completed and 3D printable object.

 

[VIRTUALENVIRONS]

3 minutes ago, Jeff Prince said:

his can be accomplished using Loft in the 'no rail' mode, but there are many other ways too.

Jeff, what are you talking about.  You are making this way to complex.

[Jeff Prince]

4 minutes ago, VIRTUALENVIRONS said:

Jeff, what are you talking about.  You are making this way to complex.

 

it's two minutes of work.

I thought you had company over....

 

[VIRTUALENVIRONS]

I do have company over and several glasses of wine.  BTW...where have you been?  Forum is boring without you.....for me anyway.

 

 Heading out to the gazebo now.  

 

In many ways I am happy you posted that file though.  It shows your NURBS "kung fu" is getting stronger.

 

Instead of breaking the curve into sections (good thinking), compose and rebuild the curve using multiples of the point.  For example, the rebuild shows 7 points, make that 77, 84,91, etc.

[VIRTUALENVIRONS]

@Rowboat  There are a number of ways to do this as you can see from my conversation with Jeff.  There are still more ways and I have included one that I think you will find interesting.

Your particular problem lent itself well to the methods shown.  More complex lofts may need deeper preparation

 

NOTE: for those watching also, this tutorial shows how to get NURBS curve start points of extracted symmetrical objects the same.

 

 

 

[Jeff Prince]

18 hours ago, VIRTUALENVIRONS said:

where have you been?

 

Spending time with my mountain bikes.

 

18 hours ago, VIRTUALENVIRONS said:

Instead of breaking the curve into sections (good thinking), compose and rebuild the curve using multiples of the point.  For example, the rebuild shows 7 points, make that 77, 84,91, etc.

 

It's effectively the same thing, but I think your cutting solution is slicker, especially with non-symmetrical geometry.

 

How do you propose he 3D prints your solution without additional work?

[VIRTUALENVIRONS]

7 minutes ago, Jeff Prince said:

How do you propose he 3D prints your solution without additional work?

I haven't given that any thought as he did not ask. 

 

Your cutting solution is great, good thinking.  NURBS are not really a known science.

 

This problem was quite simple.  Extract, loft and if you don't care if it is symmetrical, then all good.  But things change in complex areas that have never been discussed on the Forum.  Not sure they ever will.

 

 

[Rowboat]

22 minutes ago, Jeff Prince said:

 

Spending time with my mountain bikes.

 

 

It's effectively the same thing, but I think your cutting solution is slicker, especially with non-symmetrical geometry.

 

How do you propose he 3D prints your solution without additional work?

 

 

Man, I bought a full squish canyon in February but its been so hot in TN this summer I've only been on it like 3 times 🤦‍♂️


 

3 hours ago, VIRTUALENVIRONS said:

@Rowboat  There are a number of ways to do this as you can see from my conversation with Jeff.  There are still more ways and I have included one that I think you will find interesting.

Your particular problem lent itself well to the methods shown.  More complex lofts may need deeper preparation

 

NOTE: for those watching also, this tutorial shows how to get NURBS curve start points of extracted symmetrical objects the same.

 

 

 

 

 

This was a huge help to me! Thank you so much for your help here.

I've combined this build with my previously drawn objects. It is definitely a bit rough around the edges as you will see but I think that this will work with what I'm trying to accomplish and my coworker says he should be able to print it. 

Vent_shared file.vwx

Edited July 31, 2025 by Rowboat

[VIRTUALENVIRONS]

29 minutes ago, Rowboat said:

coworker says he should be able to print it. 

Good stuff.  Well done.  I just sent your model to CINEMA 4D and activated Backface Culling to check if the normals are in the right direction and they are.

 

Good luck with the Printing.

Edited July 31, 2025 by VIRTUALENVIRONS

[VIRTUALENVIRONS]

34 minutes ago, VIRTUALENVIRONS said:

Your cutting solution is great, good thinking.

Hi Jeff, I did not mean to put that line in, cutting and pasting.  What I meant to say was your solution was very creative thinking.

 

regards.

[Jeff Prince]

45 minutes ago, Rowboat said:

Man, I bought a full squish canyon in February but its been so hot in TN this summer I've only been on it like 3 times

It will be cool before you know it.  I rode last night, it was 106 when we started.  I can do about 2.5 hrs in that and I'm literally cooked.

This is how I get rid of the weak brain cells 🙂.

Since we are on the topic...I just built this one up from a frame for enduro/park riding. Longest bike I own at 180 front/165 rear.

 

 

 

 

53 minutes ago, VIRTUALENVIRONS said:

NURBS are not really a known science.

 

You've been saying that for over a year, but it makes no sense.

It's SubD that is largely overlooked and most people don't care to understand 🙂

 

[Steve S.]

There is a lot of stuff online and in schools about Nurbs with regards to the manufacturing world.

If you take a course about Alias or Catia, you are going to learn about Nurbs

 

For anyone interested in seeing what high end Nurbs modelers can do ————

 

Autodesk Alias has a free learning version and there is a lot of online material & videos about doing surface modeling with Alias, which is based on Nurbs.

https://www.autodesk.com/campaigns/alias-learning-edition

 

ICEM Surf is another high end Nurbs modeler

 

Siemens NX has a free learning version but I think it might be limited to a year.

 

Dassault Catia does NOT have a complete free version. But I think they have a version at reduced price for students.

 

Rhino is another good nurbs modeler

 

Of course, there is Plasticity

 

And there is MOI, another Nurbs modeler

 

One guy just posted this link in the Plasticity Discord today ———

https://help.autodesk.com/view/ALIAS/2024/ENU/?guid=GUID-A23E9E8C-6D6B-41AD-A0AB-3E98183FBC2E

Nothing earth shattering in the article above.

Basic to anyone that has been using Nurbs for awhile.

But good for those new to Nurbs.

 

One of the commands of Plasticity — REBUILD — gives great results quickly with minimal effort

Take a look at the video in this post. It was of an online bitmap converted to SVG, and then brought into Plasticity to smooth. Out of a curve with 93 vertices and 180 CV’s, Plasticity got it down to a 4 degree 1 span curve in a few seconds.

And realize I could have easily upped the DEGREES of the curve if I wanted it to follow the original more closely. But I opted for 4 degrees as it gave a very smooth comb.

 

The COMB used at the end of the video is widely used by Nurbs modelers.

It amplifies any rough or bumpy spots in your curves

The end of the TINES generated a very smooth curve which indicates that this 4 degree curve will work great in surface modeling.

 

This COMB is also shown in the link to the Alias article above

 

The first 4 programs mentioned above, are used primarily by car manufacturers and in product design

I believe the entry level price on the cheapest of these programs is over $5,000 a year

 

Can’t remember exactly, but one guy in the Plasticity Discord mentioned how the company he worked for was using NX I believe, and said that with the software options they had, they were paying something like $26,000 or $28,000 a year PER SEAT.

 

I read another place where someone said Catia, with various options, was costing $60,000 per year per seat.

So if a lot of people aren’t aware of these programs, the cost probably has a something to do with it.

 

Lastly I will say this, if you want to learn about Nurbs on the cheap, download the free trial version for Plasticity. This will get you and invite to join the Plasticity Discord. There is a whole lot of very knowledgeable people in that forum.

 

@Jeff Prince

Nice bike. I miss my riding days. But the mountain lions are something I no longer feel comfortable coinciding with.😅

 

Edited August 1, 2025 by Steve S.

[VIRTUALENVIRONS]

I suppose I should have said "Vectorworks NURBS are not a known Science.

 

I think this is a true statement.  The various 3D NURBS modules in Vectorworks remain largely unexplained after all these years.  There are many good tutorials on the initial use of the tools, but not in the context of why you would use them or more importantly, how they all work together.  For example, standard 3D tools, the 3D NURBS tool palette and 3D Power Pack are really one set of tools, but appear to be three.  Many of the 2D tools and commands are used for 3D  modelling.

 

I have noticed since joining the Forum in 2022 that users often ask is there a way to do this like Rhino 3D or similar, which leads me to believe they are trying to learn how to use VW's through another program.     Having said that, I see that less and less, which also leads me to believe that users are starting to embrace VW's NURBS.