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ginger04

3D locus in a site model

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Hi!

I have a site model created from 3D polygons (existing contour lines) and I want to enlarge the site model by putting some points (3D locus) with known Z value (height; there are at different places on a plan. How these points can be taken into consideration while creating a site model?

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This should work just as you expect, and hybrid site models built from both 3D polys and 3D loci appear to work fine after some brief testing.

If you want to add points to an existing site model, right-click on it and select "Edit Source Data", then create the points. Or, copy-and-paste them if they already exist in your drawing outside of the site model. After exiting out of the source data, click "Update" on the object info palette for the site model, and the points should be incorporated.

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10 years later I have this exact question. I added the 3d loci to the site data using edit source data... it does not work. VW2018 SP2.

Any suggestions? 

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Adding 3d loci to the site model source data works for me and I am using VW2016. Maybe what is happening is that you are trying to make the site model bigger by adding 3d loci beyond the boundary of the current site model but not updating the site model crop object?

VW by default creates a site model crop around the boundary of the original site model source data. I've quickly tested and found that adding 3d polygons to the source data will automatically redefine the extents of the site model crop, however adding a 3d loci does not. I.e. the site model crop does not change if you add 3d loci beyond the extent of the current site model but it does change if you add 3d polygons.

 

I suggest that you try, (after adding the 3d loci), right clicking on the site model, click edit site model crop, and delete the crop object. 

 

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I've actually been doing exactly this today (first couple of days playing about with site models)

 

Was pleased to find that I can use a mixture of polyline contours and 3d loci.

 

One thing I've noticed is that using loci seems to provide more precise control.

 

For example, I drew a closed polygon, as a contour at a certain level, thinking this would give me a flat plane at that level. But what actally happened was that adjacent landscape spilled over into it. So it's like it just takes contours as an approximation and does some kind of smoothing between them. I could see that the site model had drawn its own contour at my desired level that didn't follow mine exactly; it seemed to be interpolated somehow from other information/levels nearby. Is this intended behaviour?

 

I found that if I defined the edge of my flat plane with a string of 3d loci at the appropriate height, I got a more precise result.

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Yes the site model has to interpolate terrain and depending on which 3D setting you use the interpolation will be slightly different.

 

typically I think it is the vertex points of the lines that dictate the model. However I have successfully used 3D polylines to accurately model linear terrain like road kerbs, top of banks etc. I.e the whole line rather than just the vertexes seem to dictate the site model contours.

 

one thing To be careful with is that 3D ploys at different heights used for the site model source data can't cross each other this just confuses the model.

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33 minutes ago, Boh said:

 I have successfully used 3D polylines to accurately model linear terrain like road kerbs, top of banks etc. I.e the whole line rather than just the vertexes seem to dictate the site model contours.

 

Not quite sure what you mean by the whole line... do you mean you use a 3d polyline with varying Z height to define edges?

 

 

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To illustrate what I mean about the generated contours not matching the contours I give it, see this screenshot. The line highlighted in orange is a polyline set at 2000, but you can see in the light green generated contours that the 2000 line deviates quite a bit from mine (including at the vertices). On the other hand, where I've placed loci, the generated contours pass through them exactly.

Screen Shot 2018-02-20 at 19.15.13.jpg

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1 hour ago, line-weight said:

 

Not quite sure what you mean by the whole line... do you mean you use a 3d polyline with varying Z height to define edges?

 

 

Yes a 3d polyline with vertexes at different z heights

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2 hours ago, line-weight said:

To illustrate what I mean about the generated contours not matching the contours I give it, see this screenshot. The line highlighted in orange is a polyline set at 2000, but you can see in the light green generated contours that the 2000 line deviates quite a bit from mine (including at the vertices). On the other hand, where I've placed loci, the generated contours pass through them exactly.

Screen Shot 2018-02-20 at 19.15.13.jpg

Something isn't right as even the vertices of the orange poly don't match the displayed contours. Check if that poly is a 3d polyline (not a polygon in 3d space) in your site model source data and that it isn't conflicting with other source data.

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1 hour ago, Boh said:

Something isn't right as even the vertices of the orange poly don't match the displayed contours. Check if that poly is a 3d polyline (not a polygon in 3d space) in your site model source data and that it isn't conflicting with other source data.

 

It's a 3d polygon.

 

 

 

1 hour ago, Boh said:

Yes a 3d polyline with vertexes at different z heights

Interesting, I will have to experiment with this.

Edited by line-weight

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1 hour ago, line-weight said:

 

It's a 3d polygon.

 

After further investigation - I found that it was a 3d polygon that had somehow ended up not parallel to the ground plane - so its vertices were all at different heights (I was just looking at the object height in the OIP).

 

So that explains it.

 

 

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21 hours ago, line-weight said:
22 hours ago, Boh said:

Something isn't right as even the vertices of the orange poly don't match the displayed contours. Check if that poly is a 3d polyline (not a polygon in 3d space) in your site model source data and that it isn't conflicting with other source data.

 

It's a 3d polygon.

Yes I don't think polygons (even if in 3d space) are valid as site model source data. They need to be 3d polylines, 3d loci or stake objects.

You can just use 3d locii however i prefer 3d polylines even if it is only their vertices defining the site contour as it helps group them into one object rather than having a whole bunch of 3d locii. 3d polylines with vertices at varying z heights are also typically imported into VW from surveys dwg files which are then often used to create DTM's.

 

I've done a quick site model with 3d polylines in it as source data. I've also duplicated the polylines outside of the DTM along with stake objects sitting on top of the DTM surface. You can see how the polys relate to the updated DTM in top/plan as well as in various 3d display styles. See screen shots attached. Note they accurately define the DTM contour in 3D mesh and 3D contour which are the ones I tend to prefer.

 

A cool little trick too is for your proposed DTM you can simply place 3d polylines, 3d loci or stake objects into a class called "Site-DTM-Modifier" and they will automatically become site modifiers. Instead of using a site modifier tool I have often simply just created 3d polylines for things like the edge of a new path or driveway and placed them in this class. You get a clean edge and it is easy to edit.

 

Hope all that is helpful!

Cheers

Edit: the "poly"s referred to in below screen shots are 3dpolylines, not polygons!

Edit 2: the "poly"s referred to in below screen shots are 3d polygons, not polygons! (I don't think there is such an object as a 3d polyline...)

 

2D plan.JPG

3D MESH SOLID.JPG

3D GRID.JPG

3d Contour.JPG

Edited by Boh

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@BohThanks for the comments, yes they are helpful.

A 3d polygon *is* a 3d polyline, isn't it? Or are there two separate types of object?

 

As you'll see from my subsequent post above, I worked out what was going on with my polyline/polygon, it unintentionally had different z-heights at the vertices, so was like the red one in your examples.

 

I've realised that when editing the source data, it's possible to look at it in a 3d view (frustratingly not able to e save as a saved view) which is a good way of checking things when unexpected results are happening.

 

I've played around a bit with using 3d polylines as edges as you suggest. I wondered if placing two of them, one directly 100mm above the other, would allow me to create a vertical kerb edge but that doesn't seem to work.

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Hmm apologies, I may have confused you in my previous post as I am getting my line naming slightly wrong. I've edited my previous post:

19 hours ago, Boh said:

 

Edit: the "poly"s referred to in below screen shots are 3dpolylines, not polygons!

Edit 2: the "poly"s referred to in below screen shots are 3d polygons, not polygons! (I don't think there is such an object as a 3d polyline...)

 

 

So i've done a little research and there are a few types of "polys":

 

"polygons" are flat polys with only corner vertices. They may not be on the layer plane or horizontal but they will be flat. If you change one of the vertices of a polygon with the reshape tool to any of the other vertice types (fillet/spline/bezier etc) then you will see in the OIP that it has changed from a "polygon" to a "polyline".

 

A "polyline" can have any of the vertice types but is still flat.

 

You can convert either polygons or polylines to "3d polygons". Polygons and polylines cannot be used for site model source data but 3d polygons can.

 

3d polygons do not need to be flat (i.e. their vertices can be moved to any z height) but like 2d polygons they can only have corner vertices. If you convert a rounded polyline to a 3d polygon the rounded portion will be broken down into a bunch of straight segments. 3d polygons viewed in top/plan view have no fill.

 

Note that a polygon located in 3d space is not a "3d polygon".

 

On 2/21/2018 at 8:17 AM, line-weight said:

To illustrate what I mean about the generated contours not matching the contours I give it, see this screenshot. The line highlighted in orange is a polyline set at 2000, but you can see in the light green generated contours that the 2000 line deviates quite a bit from mine (including at the vertices). On the other hand, where I've placed loci, the generated contours pass through them exactly.

 

So coming back to your site model issue was the poly in your site model source data an actual "3d polygon" or just a polygon sitting in 3d space? If the former then it should modify your site model.

 

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23 hours ago, line-weight said:

 

I've played around a bit with using 3d polylines as edges as you suggest. I wondered if placing two of them, one directly 100mm above the other, would allow me to create a vertical kerb edge but that doesn't seem to work.

No a site model can't have vertical or undercut terrain. If you offset the polys slightly (say a few mm) then you'll get a close approximation of a vertical.

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16 hours ago, Boh said:

Hmm apologies, I may have confused you in my previous post as I am getting my line naming slightly wrong. I've edited my previous post:

 

So i've done a little research and there are a few types of "polys":

 

"polygons" are flat polys with only corner vertices. They may not be on the layer plane or horizontal but they will be flat. If you change one of the vertices of a polygon with the reshape tool to any of the other vertice types (fillet/spline/bezier etc) then you will see in the OIP that it has changed from a "polygon" to a "polyline".

 

A "polyline" can have any of the vertice types but is still flat.

 

You can convert either polygons or polylines to "3d polygons". Polygons and polylines cannot be used for site model source data but 3d polygons can.

 

3d polygons do not need to be flat (i.e. their vertices can be moved to any z height) but like 2d polygons they can only have corner vertices. If you convert a rounded polyline to a 3d polygon the rounded portion will be broken down into a bunch of straight segments. 3d polygons viewed in top/plan view have no fill.

 

Note that a polygon located in 3d space is not a "3d polygon".

 

 

 

 

 

Yes, your breakdown of the various polylines, polygons, etc matches what I've come to understand having fiddled around with things over the past couple of days.

 

One thing I'm still a bit confused about though... like you say, 3d polylines can only have corner vertices...but I'm sure I've seen somewhere talk of dealing with curved contours and how they are interpolated. And in the "site model" settings there's a setting for "segmentation length" which mentions curved contours:

 

 

Screen Shot 2018-02-22 at 12.43.22.jpg

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16 hours ago, Boh said:

 

 

So coming back to your site model issue was the poly in your site model source data an actual "3d polygon" or just a polygon sitting in 3d space? If the former then it should modify your site model.

 

 

Yes it was a 3d polygon. The issue was that its vertices were at different z heights. Once I'd understood this, it all made sense.

 

I think it's easy to accidentally only move a vertex when you want to move the whole polygon, and vice versa, because you have to watch which option you've chosen in the dropdown in the 3d polygon OIP, as per screenshot. So I've learnt that this is something to be careful about when editing the source data.

 

 

Screen Shot 2018-02-22 at 12.46.15.jpg

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4 hours ago, Boh said:

No a site model can't have vertical or undercut terrain. If you offset the polys slightly (say a few mm) then you'll get a close approximation of a vertical.

Yes, this works.

 

In practice though I think I've decided it makes sense to draw things like kerbs as separate objects on top of the surface, because then I have more control over which lines are visible in top/plan view. Because the site model doesn't know to show a line where there's a sharp drop in level like this. Just a step in the contours. I suppose the other option is to draw the line in manually in 2D for top/plan purposes but this won't update automatically if i make changes to the model in the future.

 

It might be nice if in the source data you could draw certain 3d polygons and specify for them, "draw this edge as a line in top/plan view".

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9 hours ago, line-weight said:

One thing I'm still a bit confused about though... like you say, 3d polylines can only have corner vertices...but I'm sure I've seen somewhere talk of dealing with curved contours and how they are interpolated. And in the "site model" settings there's a setting for "segmentation length" which mentions curved contours:

Is that a VW2018 feature as I can't find it on VW2016 or 2017?

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9 hours ago, line-weight said:

Yes, this works.

 

In practice though I think I've decided it makes sense to draw things like kerbs as separate objects on top of the surface, because then I have more control over which lines are visible in top/plan view. Because the site model doesn't know to show a line where there's a sharp drop in level like this. Just a step in the contours. I suppose the other option is to draw the line in manually in 2D for top/plan purposes but this won't update automatically if i make changes to the model in the future.

 

It might be nice if in the source data you could draw certain 3d polygons and specify for them, "draw this edge as a line in top/plan view".

A kerb could be drawn as a 3d polygon and placed on the "site-dtm-modifier" class. It would then be visible as a line in top plan view as well as modify the DTM.

 

Downside is that it would only be part of the proposed DTM (so would effect cut/fill calcs), also there may be other modifiers on this class that you don't want to be visible.

I usually just end up doing a seperate 2d line for my top/plan view...

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16 minutes ago, Boh said:

Is that a VW2018 feature as I can't find it on VW2016 or 2017?

That's in 2018 yes. And I've just had a look in 2017 and it's not there.

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FYI, NURBS curves set to the Site-DTM-Modifier class will also modify the site model. 

 

 

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