How to parse room dimensions from .rad model ?

Hello everyone,

It is a kind of weird question but thought to hear your views.

Let's say, someone gave me a .rad file which is a model of a rectangle
room. This model has many polygons for surfaces such as walls, windows,
luminaire, furniture etc.

How shall I develop a method/function that can parse this .rad file and
return me back the room dimensions. I have no additional information, like
walls' name variable etc.

I want to make a simple java method for that. I am not using any CAD API.

Is it possible? Please don't bash me for my stupid question.. :stuck_out_tongue:

Best regards,

Hi Vaib,

Yes, that’s generally how folks do it with Radiance, is rotate the sky to mimic an off-axis building footprint. It’s done for the reasons you cite, as well as for efficiency in the octree. There are a few posts on this on the archives.

- Googs


From: Vaib <[email protected]<mailto:[email protected]>>
Reply-To: Radiance discussion <[email protected]<mailto:[email protected]>>
Date: Wednesday, February 12, 2014 at 3:34 PM
To: Radiance discussion <[email protected]<mailto:[email protected]>>
Subject: Re: [Radiance-general] How to parse room dimensions from .rad model ?

Thank you Dr.Greg. It makes sense now.

I am just curious to know your opinion on changing the site's North by rotating the Sky. Do you think it is a good practice? Because on rotating the building/room, one cannot take full advantage of other good programs such as getbbox and/or getinfo -d.

On 12 February 2014 23:18, Greg Ward <[email protected]<mailto:[email protected]>> wrote:
The size returned by "getinfo -d octree" is the cube side length, which is of course the same in all three dimensions.


From: Vaib <[email protected]<mailto:[email protected]>>

Date: February 12, 2014 2:08:22 PM PST

getbbox will solve the issue at hand. Rooms/scenes are mostly right rectangular prism; and also they are normally kept aligned with principal axes, only the sky (if with sun) is rotated to change the North. I guess, to rotate the sky instead of the scene must be preferred for modeling architectural scenes in Radiance.

Further, just out of curiosity: getinfo -d foo.oct gives [Xmin, Ymin, Zmin, Size] of the bounding cube (I guess cuboid too?). I couldn't figure what does Size mean? Is it Xmax or Y/Zmax?

Thank you for your time!

Best regards,

On 7 February 2014 18:47, Greg Ward <[email protected]<mailto:[email protected]>> wrote:
Yes, let's keep this on the general mailing list. The dev list is primarily for development/debugging issues.

The getbbox command will give you a tight box (right rectangular prism) on the entire scene, whereas oconv will report an enclosing cube. However, this won't help you much if your space is non-rectangular or not axis-aligned.

A general tool for extracting the walls from a room is technically the 3-D convex hull problem. There are programs out there to compute this, but I haven't played with them.


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