# Embankment

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Hi, I am beginner, so please help. Would like to create 3d object: ascending embankment, from 0 to 3 meters. Problems are it is straight in the beginning and then turning left, so two sides are of different length (7.2 m of difference); width of the embankment is also changing (from 3.1 to 5 m). So when I used "extrude" and then "tapper face" tool, in result the beginning of the embankment looks like in pictures below (0.48 m of difference in level between left and right border). I guess it is because of the irregular shape of embankment. Is there any way to nivelate it? Or should I convert it to NURBS? Would appreciate your help!

You want to do something that is actually a bit tricky in Vectorworks, more so than it first appears, for a number of reasons.

And if you can make sense of that, also have a look at the method described here by @axhake:

If you are a beginner in VW you might find some of that a bit hard to follow, but you might also learn quite a bit of useful stuff!

It's possible there is a simpler way to deal with your particular problem that would be "good enough", but if you want to do it accurately I'd suggest you look at these links.

@jantopol would making a straight tapered ramp first then using the Deform Tool to bend it work for you? Like @line-weight says this might not give you the accuracy you require but it will certainly give you the shape.

Thank you @line-weight and @Tom W.! Will try it today. Best wishes, jt

Here's another take with simple loft.  It would help to have the plan view, but this seems close.

In v2022, the NURBS faceting seems minimal.  So maybe they improved, or perhaps the scale here is within reasonable bounds.

Prior to loft, I adjusted the sloping curve vertices with Reshape tool, constrained to z, so that the pathway ends are tangent at connections to overpass and to ground plane.

The loft creates a hollow object with open end.  If solid is desired, Add Surface the NURBS rectangle, or use the 3d Power Pack>Create Planar Cap (makes a NURBS Surface), then Add Solids, then Convert to Generic Solid.

This can also be done with Aligned Slab, but I think that started in v2019, or some other techniques if a Site Model is used.

-B

That seems a sensible way of producing a "good enough" result but I think I'm right in saying that it doesn't create a ramp that is perfectly level side to side all the way along (this can be seen by making a section through it, perpendicular to its centre line, at various points). Achieving this in fact is one of the things that's more tricky than it forst appears, when making something like this.

Interesting you think the faceting is less bad than previous versions @Benson Shaw - are you sure though? I can still see it, and one of the problems which the faceting causes, which is that it's virtually impossible to make two perfectly matching curved edges from NURBS curves, is visible in this model if you look at the join between the "core" ramp and the sloping side that you add in your last step. If you zoom in you can see this in OpenGL view, and you can also see it in a section (even with 3d conversion set to "very high".

Images below are a cross-section taken from the model.

@line-weight Right on with closer look.  Those nasty facets are still with us.

Regarding level side to side - original concept did not aim at that.  But it is possible.  Rather than center line, this example makes the level consistently normal to the inner curve.  Can also be done with DAP from a center line but then requires adjusting the rectangles to meet both curves, not difficult. Also, would help to have a plan view to understand how the path splays.

Regarding the mismatched NURBS - I get a best result by lofting a combined core/side bank (Design Layer 3). If desired, sectioning along the joint produces separate banks.  Not perfect match, but much better than the separate lofts.  Another workaround would be to create a separate side bank a bit low and embedded a bit sideways into the core.

A vwx loft seems to "pull" the surface edges a little tighter than corresponding NURBS curve guides, eg the visible outer curve (green) of the side bank. Also, there is some faceting of the horizontal surface, especially noticeable as a fold near the foot of the ramp.  Who knows, maybe these imperfections in vwx NURBS will never be resolved.

I did not attempt a model with more stations, but that might produce a loft closer to the planar guides.

I made an intermediate variation in Design Layer 2, experimenting with establishing the level line across the path.

I would be interested to know how the NURBS from vwx port into Rhino or other.  Are these vwx NURBS curves and lofts faceted the same way in the more advanced NURBS modeling software?

OK trying to help the OP here.

-B

26 minutes ago, Benson Shaw said:

A vwx loft seems to "pull" the surface edges a little tighter than corresponding NURBS curve guides, eg the visible outer curve (green) of the side bank. Also, there is some faceting of the horizontal surface, especially noticeable as a fold near the foot of the ramp.  Who knows, maybe these imperfections in vwx NURBS will never be resolved.

yes, this is one of the problems with this kind of method in VW, you don't really have full control of exactly what path the curves end up following. As you say, it's visible in plan at the top of the ramp, in the "outer" curve lines which aren't at right angles to the end of the ramp and this becomes a problem if you want a proper tangential transition between one section of ramp and another. I think the best you can do is get it nearly right via a bit of trial and error.

The method described by @axhake in the thread I linked to further up addresses this which is why I'd recommend anyone who needs to produce properly accurate models to have a close look at it.

@Benson Shaw hope this doesn't come across as criticism of your suggested solutions; the problems are ones caused by the way VW works.

@line-weight  no worries, i sussed your intent.

I think it’s worth hammering on these NURBS issues in the wishlist and other forums, and, when appropriate, with vwx staff at events such as version rollouts, design summits, training seminars, etc.

-B

On 1/21/2022 at 6:16 AM, Benson Shaw said:

@line-weight  no worries, i sussed your intent.

I think it’s worth hammering on these NURBS issues in the wishlist and other forums, and, when appropriate, with vwx staff at events such as version rollouts, design summits, training seminars, etc.

-B

I don't feel too optimistic about that producing any results when it's seemingly too much to ask, even for the help documentation on NURBS to be accurate...

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