Radiation analyses grid

Dear all,

I am a new follower (hi everybody) and I am trying to develop some nice tools for supporting preliminary sustainable analyses based on GH and Ladybug.

I have some troubles with the solar radiation analyses: grid size input parameter does not consider the grid as I'd like.

I'll try to explain better: if I draw a mesh I can divide it in many part as I want depending on 'u' and 'v' directions, while for the 'grid size' command I can only set an average value.

This point is not usually relevant, but if I have to consider the shading effect on the facade (for example vertical fins), I need to set the grid with the same size of the shadings step in order to perform the analysis correctly (i.e. avoiding the analysis points of the grid correspond to the shadings).

Please consider the picture attached: although I have set the 'grid size' with the same shading step, the grid points aren't comparable with the shading steps.

How can I do?

Thanks for your help.

Attachments:

Immagine.png, 29 KB

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Permalink Reply by Chris Mackey on November 3, 2014 at 10:38am

Hi Ricardo,

Thanks for posting. Usually, the idea with the grid size is that you make it a lot smaller than your Rhino geometry so that you can get a sense of how each shade casts shadows over the window. I am not so certain if your method of aligning a grid with the shades is really going to be that accurate since it is only going to ray trace from that one point in between the two shades (in fact, I think having a mis-aligned grid is probably going to help you get an average radiation value over the window that is more accurate).

Still, if you want to align things perfectly, there is a very easy way to do what you want with the Ladybug components, which is to connect meshes to the "_geometry" input of the Radiation Analysis component instead of breps. When you connect up breps, the component uses the _gridSize input to mesh the geometry based on that grid size but, if you input a mesh, the component will use the existing faces of that mesh and perform radiation analysis on each one of those faces.

So, to get full control over the density of grid sizes, all that you have to do is mesh your geometry before connecting it to the Radiation Analysis component using the native grasshopper components that you mentioned, which divide up the surface based on UV.

Let me know if that makes sense and answers your question.

-Chris

Permalink Reply by Riccardo Diaferia on November 4, 2014 at 2:49am