Can't loft between nurbs

[Amber Hine]

Having trouble lofting between the two NURBS in this file. 

 

All I want to do is create a surface between them and then give it a thickness to create a roof top edge, It just for visualisation- So I have tried various methods to create this effect and I can't seem to get there... any ideas, hairbrained or otherwise would be appreciated...

 

https://www.dropbox.com/sh/gj0ugurf8om9bpm/AADPyhCoYk8BvihkHp3TeYHKa?dl=0

[VIRTUALENVIRONS]

I could not open the file.  Must be 2023.  Post it as 2022 and I could have a look if no one else comes up with a solution.

 

 

[Jeff Prince]

3 hours ago, Amber Hine said:

Having trouble lofting between the two NURBS in this file. 

 

There aren't two NURBS in the file... Just two meshes that lack a fill.  Here's what it looks like:

 

 

So you are trying to create the "facia" between these two meshes like the yellow surface depicted here?

 

 

If so, you can extract the edge of one of your meshes by converting it to NURBS and then use it as a path for an Extrude Along a Path where you just need to draw the profile of the "facia".

 

In the future, please purge your drawings before uploading.  This file was over 140mb originally, but only 1mb after purging...

Edited May 20, 2023 by jeff prince

[VIRTUALENVIRONS]

Good methodology.   Will the original surface shell?

[Jeff Prince]

1 hour ago, VIRTUALENVIRONS said:

Good methodology.   Will the original surface shell?

 

Not without some work.  I attached v2020 file so you can see what it looks like and propose some alternative methods.

 

 

Northplace purged v2020.vwx

[Amber Hine]

It would certainly be nice to just shell it! 🤣 

[VIRTUALENVIRONS]

Thanks for the file Jeff.

 I did not catch this right away.  First Image.  Makes it tricky to anything with.

 

 

 

Jeff method is probably to the "go to" method, but I worked out another one because it's Saturday afternoon and raining here.   I appears the surface follows NURBS math, so I Just picked off the top curve, dropped it and lofted the surface to make a fill.  The file is included, but it has the weird joint shown above.

CURVES.vwx

 

 

 

 

 

[Jeff Prince]

@Amber Hine You know, a little more context might help with a better solution.  How were these weird surfaces created initially?  It reminds me of something generated from a site model.

 

If that's the case, you might enjoy this old trick....

 

 

[Amber Hine]

2 hours ago, VIRTUALENVIRONS said:

 

Jeff method is probably to the "go to" method, but I worked out another one because it's Saturday afternoon and raining here.   I appears the surface follows NURBS math, so I Just picked off the top curve, dropped it and lofted the surface to make a fill.  The file is included, but it has the weird joint shown above.

 

 

So that is exactly what I had been trying to achieve, but the loft tool kept failing- was it just because I missed the overlap- I feel like a right plonker! thank you!

[Amber Hine]

2 hours ago, jeff prince said:

@Amber Hine You know, a little more context might help with a better solution.  How were these weird surfaces created initially?  It reminds me of something generated from a site model.

 

If that's the case, you might enjoy this old trick....

 

 

Fabulous, this will be helping with my next bit- it was generated using a 3D poly and 3Dloci as a referance point, that were also used to make a site model- think you helped with that a little last week too 🙂 many thanks again 🙂 

[VIRTUALENVIRONS]

7 minutes ago, Amber Hine said:

I feel like a right plonker!

Lots of good info on this thread for reference.

 

IF I had a dollar for every time I felt like an idiot for missing something, I would be rich.

 

I would love to know where or how you derived this surface.  To be honest, I can't figure out what it is.  I think it is a surface, but because that joint twist over itself, it may simply be blocking all attempts to modify it. 

 

I did not extract the curves.  I used a different method that is difficult to explain in words, but it is a method rarely used, so let's skip it for now.  If you have more of these, I can do a short video.

[Benson Shaw]

Great discussion and challenging question.  Some details from my explorations:

 

1.  Using the perimeter of the mesh to create a facia seems promising, but many problems, esp at that entry/stair area.  Other possibilities I did not try - A) Add a component to the original site model (thickness of facia height). Convert a copy to Mesh and isolate the edge shapes.  Problem is it has no thickness.  B.) Use the 2d layer plane roof outline as source for new walls. Fit the walls to the mesh once at top. Move the mesh down and fit walls to bottom. Walls can have thickness or components for the facia. Acute angle at stair will need special treatment.

 

2.  Using this mesh, my EAP struggles to complete a continuous form. Gaps and miss fits where inclines vary.  Great for distant visual, but not so good for construction.  I could not easily solve this.  Lots of extra modeling required at many joints.

 

3.  Lofting (No Rail) also great for visual, but no thickness.  I tried Birail Sweep too, but no joy except in smaller sections, so more modeling to correct at joins, similar to EAP.  Too bad this loft doesn't shell. Even converting to Add Solid and Generic Solid will not shell the whole object.  Also, shells go normal to surface, so gaps will need filling (Maybe Stitch and Trim could help?)

 

1st step is getting the perimeter.  Easiest is Convert to 3d Poly.  Mesh evaporates, leaving the perimeter.  No need for Extract tool.

 

Some files attached.

 

-B

Northplace Facia b v2023.vwx

[Jeff Prince]

39 minutes ago, Benson Shaw said:

<a lot of confusing statements>

 

The method I posted, while not the only one possible, is probably the easiest and fastest way to do it.

No drama, no problem areas of geometry, it just works... check the attached file for witchcraft and such.

 

doesnt have to be difficult.vwx

[Benson Shaw]

2 hours ago, jeff prince said:

easiest and fastest

@jeff prince  Cool, thanks for looking at my file!  Ummmm . . . I don't think my post above contains any phrase about "...confusing statements".  Especially unlikely in that I didn't find any confusing things in your or other posts!

 

The EAP profile in your file is a straight NURBS curve. It has no thickness. Same resulting shape as the loft no rail. Great for visualization.  I got there easily, but am also exploring thickened context.  Edit your profile to include some thickness, eg a NURBS or 3d poly rectangle, to see missing faces and mismatched segment joins. Attached find image and your file modified with thickened profile.

 

@all - So far this thread is fun vwx modeling technique.  I believe underlying concept derives from a roof top park DTM?  I wonder what is intended or possible retaining system for the proposed landscape and users thereof. And efficient modeling to match.

 

-B

 

 

Isn't difficult 2.vwx

[VIRTUALENVIRONS]

Hi Guys,

I used a different method than the ones we are pushed towards by Vectorworks.  This thinking has served me well since MiniCad 1.  Below is a short video on getting the curve.  It is quite easy and then the curve can be lofted, the loft can be shelled, etc.

 

 

[Benson Shaw]

@VIRTUALENVIRONS  First, thanks for your several posts showing your NURBS techniques.  This process of tracing an original curve to regularly spaced loci is quite helpful in many situations.

 

The traced curve you suggest here indeed lofts and shells nicely - pick each facet.  Or Add Solid and shell all in one go.  But, the shell is, I believe, unusable in this context because of gaps and uneven joins between non continuous facets.  That's the nature of a shell - normal to each surface.  Maybe a small fillet at each corner point would correct. That's something to test another day.

 

I'm trying the walls with fit to geometry next.  But might be a couple days.

 

-B

 

[VIRTUALENVIRONS]

HI Benson,

I stand corrected.....thank you.  I was doing this quickly this morning as I was behind in the "honey do" list.  I just shelled it quickly and posted.

If I was gong to pursue this further and I have not looked at this, just off the top of my head. I would select the curve and "Rebuild NURBS: with a factor of 4.  Then go through the same process and see what happens.

 

I see you post on NURBS often.  What is your main focus in 3D design.

 

Paul

[Amber Hine]

man, you guys ran away with this- love it!- I shall have to take a further look at some of your alternative solutions at some point- nice! 😄

 

Thanks for being awesome 😄