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DTM - Modifiers - drape to Surface required ?


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2 hours ago, Benson Shaw said:

Multiple grade limits or retaining edges or other site mods can be surrounded by a larger grade limit.

 

Thanks, that should help a lot. Good to know.

 

 

2 hours ago, Benson Shaw said:

Also pads can share an edge, maybe graders, too? A warning generates, but the dim updates as expected. I think Tamsin talks about that in a video about roads. Or in an old post here. Sorry, can't find now.

 

Yes, I found that too.

They can touch (and give a warning) IF they share the same height.

Otherwise they both might get ignored.

 

The most compressed source that also shares this may be that Landscape PDF Tutorial I found on VSS,

I think under Leaarning > Tutorials.

 

So it also should work with touching Texture Beds (?)

Didn't know that before so my pedestrian areas all have a 10 cm gap to roads so far.

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2 hours ago, Benson Shaw said:

Another way instead of tracing contours is Duplicate Along Path. A 3D locus on each contour. Pick optimal spacing or point count for your needs. Class or color each group. Create DTM from the groups. 

 

-B

 

That is an idea.

 

I know the linking lines between Polylines haven't any meaning for the Mesh Algorithm.

But the point why I think you should use (hard edged !) 3D Polylines is that these allow to recognize

where all points of same height are located.

Especially as you have no preview of the influence on the resulting Mesh while creating source data.

Or in cases where you "bend" some of your contours around your building borders, with connected lines

you are able to see where points of same height will "come out" behind the building again.

 

Generally I would prefer Points or Stage Objects too.

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14 hours ago, Benson Shaw said:

Another way instead of tracing contours is Duplicate Along Path. A 3D locus on each contour. Pick optimal spacing or point count for your needs. Class or color each group. Create DTM from the groups. 

 

-B

Now that's an idea I hadn't thought of, but seems perfect.  Less steps than covert to 3D polygon, simplify 3D polygon, move to new layer, etc.

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BTW

 

This is from the old VSS PDF Tutorial.

This is exactly what I don't want or can't need for Rendering Purposes :

 

FAB2018_2017-09-09_12_30_02.jpg.4cccf16d10d3cd289f5a5ac2555b56a2.jpg

 

Just a Slope between Modifiers and surrounding Grade Limits.

 

 

FAB2018_2017-09-09_12_30_25.jpg.e12adf7df64261a1cdd2e899eda3eadf.jpg

 

And such a kind of Mesh generation.

As I read it is already known that the used Meshing Algorithm doesn't fit everyones needs.

I hope there will be an improvement in VW 2018.

Edited by zoomer
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Or here a kind of source data that I may get :

 

FAB2018_2017-09-09_12_56_09.jpg.2d6041b085869c655e7f6fbc669edb5a.jpg

 

First I thought, wow, these are quite interesting geological formations.

Until I realized by watching Google earth, it is just frequency noise.

Something you can't overview if you zoomed in to draw your manual contours.

 

And this prevents you from using the automated "simplify Poly" command as it

will not find the simplified interpolation.

It might keep especially those point that are most far from the real contour and

completely change the terrain.

So at the end such source geometry contains a signal to noise ratio of at least 1:5.

Edited by zoomer
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7 hours ago, zoomer said:

This is exactly what I don't want or can't need for Rendering Purposes

A strategy might help with presentation renders if you are willing to use a separate object. This would mean working with the DTM, hiding it on its own layer/class for future use, creating a new surface object based on the DTM and placed on a visible presentation layer.

 

Here are some options:

1.  3d Power Pack>Drape Surface over the site model. I don't much like this.  Too much fooling around with the parameters, trimming, etc

2.  Duplicate in Place the DTM & send dupe to the new presentation layer.  Then Modify>Convert>Convert to Mesh.  Then in the OIP render tab, adjust the Mesh Smoothing.

3.  Same as 2, but use the DTM 3d Display>Grid and test to find best grid spacing.

 

Several problems with this, but it still might be worth trying:

• The mesh object has be traded in/out for the Site Model each time a presentation view is needed.

• Mesh needs to deleted, then recreated every time the DTM is modified.

• Smoothing causes edges at grade limits/pads to round over.

• Creating & managing new layers, classes & visibility settings

• Probably more.

 

-B

 

DTM to Mesh.png

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Yes, thanks for the comparing illustrations.

 

I also thought about the Nurbs Drape,

or maybe a Nurbs or even SubD Grid, which you arrange in 2D Layerplane to fit

your needed border and edge flow, before you finally send it to surface.

 

Problematic are these tight sloped areas where I would like to have streets and

walkways nearly level.

 

FAB2018_2017-09-09_19_35_31.jpg.f7d601f9bb2d18bab36bab6f7bf7b71e.jpg

 

Problematic are those long tight contours at steep slopes.

 

 

FAB2018_2017-09-09_19_37_44.jpg.7ea0171693f46e3c0ede7507c0f92881.jpg

 

That is my LOD - still much too high.

But you can't estimate if you zoomed at a level where you can work with Vertices.

You lose scale.

 

And you can see that I added a lot of extra points around the walkways/street.

You should not have longer line segments than the distance between contours.

Otherwise the Meshing, by nearest point connections will create edges that destroy

the form completely.

Also any "simplify Polys" would make those tight contours to overlap.

 

 

FAB2018_2017-09-09_19_38_39.jpg.71636b65785839e371b80297e8275ce5.jpg 

Edited by zoomer
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So to summarize :

 

1. Source Data is crap (signal to noise ratio)

2. Topology is complicated (sloped + detail variation + curved slopes)

3. VW DTM is limited (my opinion)

4. I have to Export for Rendering Purposes

5. I will get constant Design Changes.

 

 

my conclusion :

 

A) See Source Data as Graphic Template only, create your own DTM Source Essence.

B) Make a Copy from Contours and keep only every n-th Contour, depending on Topology Detail and Importance

C) Create Stake Points along the Contours at a distance similar to the distance between contours.

(To get kind of a Grid)

D) Try to either match or stay away from 2D Plan Detail Edges like Streets, Walkways, coming Modifiers, ...

when positioning Stakes.

E) Create a DTM from this Data Essence.

F) Use Texture Beds to separate Ares of different Materials.

G) Use Modifier Pads to create larger flat Areas and Jumps in Height.

H) At the Property Area, refine the Mesh by adding more Stake Points, according to @enson Shaw.

(Snap between to Stakes in 3D, Duplicate along Path, ...)

Edited by zoomer
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