topic Re: Extruded building heights seem wrong... in ArcGIS CityEngine Questions

Extruded building heights seem wrong...

ChristopherEstes — Mon, 04 Jun 2012 14:29:05 GMT

Hey, I've extruded my building heights with the following rule:

attr AVG_HEIGHT = 0

@StarRule
LOT -->
extrude(AVG_HEIGHT)
Volume.

But they appear way taller than they should be. I'm experienced with ArcGIS, but new to CityEngine. Any help/guidance would be appreciated. I've included a screenshot.

Re: Extruded building heights seem wrong...

boonejardot — Mon, 04 Jun 2012 14:37:02 GMT

I have not done much with regards to 3d analysis, but I recall that you may want to subtract the elevation/DEM from the building heights, that may be the problem. Perhaps someone who has worked more with this aspect can answer more thoroughly.

Re: Extruded building heights seem wrong...

TimothyHales — Mon, 04 Jun 2012 14:49:26 GMT

What is the coordinate system units of your data and CityEngine scene? Are you pulling this value from the attributes? What units should it be?

Re: Extruded building heights seem wrong...

boonejardot — Mon, 04 Jun 2012 14:54:09 GMT

Good Call thales007! Feet heights shown in meters just might look exactly like this.

Re: Extruded building heights seem wrong...

ChristopherEstes — Mon, 04 Jun 2012 15:11:20 GMT

What is the coordinate system units of your data and CityEngine scene? Are you pulling this value from the attributes? What units should it be?

The data is: NAD_1983_HARN_StatePlane_Oregon_North_FIPS_3601

The Scene is: NAD 1983 State Plane Oregon North FIPS 3601 US Feet

Though, it does seem like the buildings are being drawn more in meters than feet. I'll look into that some more. Thanks to you both!

Re: Extruded building heights seem wrong...

ChristopherEstes — Mon, 04 Jun 2012 15:43:47 GMT

Both the data and scene are in NAD 1983 State Plane Oregon North FIPS 3601 US Feet and the buildings are still looking too tall. Might there be an issue with the rule I'm using?

I found the rule on here and just subbed my height value.

attr AVG_HEIGHT = 0

@StartRule
LOT -->
extrude(AVG_HEIGHT)
Volume.

Re: Extruded building heights seem wrong...

boonejardot — Mon, 04 Jun 2012 15:50:21 GMT

Just to be clear: Your data for the building heights, is that height above sea level, or height off the ground at said location? Since your units seems to be good--according to what you have said. Let us know.
Just to reiterate, I once had to subtract the DEM heights from the building heights to get a true height for a project I worked on. Just making sure it is not something simple like this. Good luck.

Re: Extruded building heights seem wrong...

ChristopherEstes — Mon, 04 Jun 2012 15:54:53 GMT

Just to be clear: Your data for the building heights, is that height above sea level, or height off the ground at said location? Since your units seems to be good--according to what you have said. Let us know.
Just to reiterate, I once had to delete the DEM heights from the building heights to get a true height for a project I worked on. Just making sure it is not something simple like this. Good luck.

I see what you're saying and I think you're right. I've not figured out how to get terrain successfully into CityEngine yet (my DEM always looks flat, , but given the elevation, if the terrain was there, and the building heights were as they were in that pic, then they would be the right height. So, I'll pursue that angle. Thanks!