Bend an object along a nurb curve

[Neves+Creative Inc.]

Can you bend a generic solid along a spline?  Besides the bend tool, is there automated way or better tool to use to ensure it matches the spline or nurb curve

[VIRTUALENVIRONS]

I have not seen any function that does that, although I seldom use bend or distort tools.  What exactly are you trying to do? 

[Pat Stanford]

I agree with @VIRTUALENVIRONS that there are no tools/commands in VW to bend along a spline.  The Deform tool is the closest we have.

 

So you may need to do the bend in a different program and import it to VW, or can you make the part differently? Start with a part bent along the curve (extrude or extrude along path) and then to whatever other solid operations need to be done after?

[Neves+Creative Inc.]

I am making curved wall flats. Started with building frames and converting to generic solids and then creating 1/8” luana sheet turning to generic solid. I need to turn these into build drawings.  I noticed when I bent the frame then matched the Luana the size gets distorted.  The frame is 2.5 thick built from 1 x 3.   8’ wide.  The Luana sheet is 4’ x 10’.  When frame and Luana are flat they line up but after bending along the radius the Luana was too short by up to .45 inches depending on the radious.  So now I am using the arc tool to get center line arc length for each location where I am bending these wall flats as it looks like they should be built any where from .15 to .5 shorter then the final surface material (Luana).  I noticed that when I zoom in to get detailed snaps the line seems to move snaps aren’t super accurate the underlying curve some times has facets when it should be smooth and its very time consuming. 

 

Not sure if this makes sense 

[Kevin Allen]

could you use the curved wall tool and components? It won't quite show the frame, but...

[Pat Stanford]

If you want your frame to fit your Luna sheet you will either need to make sure you bend along the edge you will put the luna sheet or you will need to adjust the length of the frame before you bend it.

 

When you bend a solid, the edge you draw the original line against maintains its length. Other edged extend or shorted to maintain the end conditions.  

 

The attached image has three identical objects, a 16' x 4" rectangle horizontal extruded 8' and bent 90° along three different bend lines. Top Left was bent along the bottom edge.  The bottom left was bent along the rectangle midline. The Top Right was bent along the top edge.  I then placed Arcs along the two faces (so I could use the Arc Length tool) and moved them away for better visibility. Notice how much of a difference in length there is between the top and bottom arc length.

 

HTH

 

[Benson Shaw]

@Neves+Creative Inc. Seems like two problems here.  1st is how to draw your intended design. 2nd is how to build to the design.

 

I think best approach to drawing is extrudes.  As you found, NURBS curves and surfaces resulting from Bend, Shell, etc have facets and snap issues at high zoom levels. The math is correct (OIP lengths, areas, etc), but the graphics can get confusing.

 

Regarding draw - post back if help needed with any of this

The Luaun, the stiles, the rails - all should be represented by extrudes of 2d Polylines or other 2d basic shapes. Start with a long poly (spline is fine) for the whole curve. To determine segment for each flat, place a locus and duplicate it along path with 10' interval (or 4' if flats are standup). Use the Split tool, point mode, to cut the poly into the smaller segments at each locus.  Use each segment 3 times. Here are the basics:

1. Offset tool, Closed mode, 2.5" for the stile - extrude to 3/4" for the bottom stile. Later on, you will Duplicate and move z for top stile

2. Offset tool (other side of the poly), Closed mode, .125" for the sheet - extrude to 4' or 10' depending on orientation.

3A. Rectangle tool, 3 point rotated mode - Draw footprint of a rail (eg 2.5"x.75") on top surface of one end of the stile extrude.

3B. Duplicate Along Path (the flat segment), Tangent, Keep orig Position (uncheck the Center on Path). choose spacing or required number of rails.

3C. Extrude to height of flat less 2xstyle thickness (eg 1.5").  You may need to duplicate a rail and move/rotate to provide one at other end of stile.

 

Regarding build

I think many issues will point back to providing some tolerance. Different radii will produce different stretch/compress amounts of the 2 faces of the Lauan. Minimal amounts at 1/8", but noticeable on the drawing.  I think not to worry.  Design the frame stiles and rails to desired shape and dimension. When attaching Lauan to the frame, it may overhang (trim it!) or may come in shy (caulk or other filler).  Because of real world material and craft variances, you will never achieve perfect fit.  Lumber is not straight or even constant dimension.  Cutting the curved styles (CNC? Jigsaw by hand? Routers?) will produce variances. Parts may not assemble without small gaps. Multiple parts of cut lumber may not be EXACT to the vwx design precision. Bending the sheets may not fit intimately to the (imperfect) curves. Sheets may not be perfectly square. The frames, even with braces and corner blocks may not be perfectly square, the bent sheet tension may bow or flex the frames, etc, etc, blah, blah, buuulah.

 

Anyway, my advice, design and build the frames as close a possible to desired dimension. Trim or fill the sheet edges as needed.

 

-B

Edited January 8 by Benson Shaw
wandering among the stars

[line-weight]

I agree with everything that benson shaw says.

 

I think that trying to measure on the drawing to predict where the ends of the bent sheet material will end up, when attached, is destined for failure. If I wanted joints to be in specific locations, I would choose those positions such that the predicted edges of a bent sheet oversail them a bit, and work on the assumption that the sheets will be trimmed back on site.

 

The issues you touch upon, of faceted curves and accuracy of snapping to them, these are a bit of a problem in vectorworks in certain situations. What is and isn't a problem is a bit complicated. But I'd say that in general terms, as soon as you start doing complex curves especially things like NURBs curves in Vectorworks, then in practical terms expect to lose a bit of precision. If you are preparing drawings for some kind of high precision manufacture then VW may not really be the right tool. However... the reality of building construction is that nothing is actually that precise, and you can get away with "near enough". But it does need some careful thought in how you prepare the drawings, and some sensible allowance for tolerances.

[bcd]

9 hours ago, Benson Shaw said:

I think best approach to drawing is extrudes.

100%