topic Polygon (Align to terrain) in ArcGIS CityEngine Questions

Polygon (Align to terrain)

JeffShih — Thu, 06 Jun 2013 17:52:26 GMT

Issue:
Polygons are not aligning to the terrain correctly and do not appear transparent.

[ATTACH=CONFIG]25085[/ATTACH]

Temporary workaround:
I burned the cut block extents into texture.png and created the terrain based on the DEM. This achieves what I want visually (the ability to see the undulating curves of the terrain); however, I cannot query the attributes since it's a raster.

[ATTACH=CONFIG]25086[/ATTACH]

Goal:
Ideally, I'd like to have polygons (cut blocks) draped on top of a terrain with transparency set (to see the terrain underneath) and be able to click on it to view the polygon ID, area, status...etc.

[ATTACH=CONFIG]25090[/ATTACH]

Any advice would be much appreciated!

Re: Polygon (Align to terrain)

ScottFujikawa — Thu, 06 Jun 2013 20:04:38 GMT

Hi,
I have tried to do the exact same thing to show a parcel shape on top of the terrain. Aligning 2D shapes to the terrain only works a little, as the edges of the polygon try to align but the 2D plane of the polygon does not warp very well to the terrain.
The best work around I have is to just extract the border of the polygon using cga rules and float it slightly above the terrain.
(See my examples) However, one would have to click on the border line to see any meta data.
Best, Scott

Re: Polygon (Align to terrain)

Anonymous User — Thu, 06 Jun 2013 20:13:47 GMT

Original User: crmltd-js

Thanks for the feedback Scott. It's nice to know that I'm not the only one struggling with this.
How do I go about extracting the border of the polygon using CGA rules?

Re: Polygon (Align to terrain)

ScottFujikawa — Thu, 06 Jun 2013 20:38:22 GMT

Hi

It take 2 rules & 2 steps.
First Rule:

version "2012.1"

attr EdgeThickness = 2
attr SegmentLength = 6

@StartRule
Shape-->
offset(-EdgeThickness)
comp(f) { inside: NIL | border: Border }

Border -->
split(x) {SegmentLength: Segment}*

Segment -->
color("#FF0000")

After you assign & generate a red line will appear. Zoom in real close & click to select the whole line. Then right click and "convert models to shape"s.
Then align the shapes to the terrain.

Then layer select the new shapes and assign the next rule:

version "2012.1"

attr HeightOfBorder = 2

@StartRule
Shape -->
color(1,0,0)

Hope this works for you.