Shading Opacity

[R Dias]

Hello!!

I'd like to model a surface that is similar to a net, with a lot of little holes. Can I use a shading with a variable opacity in SketchUp to simulate this net? Is IES sensitive to the shading's opacity?

Thanks for the attention

[PCully]

Hi,

Openings (holes or windows) on shading objects isn't something that can be modelled by VE. You'd have to physically model the shading surfaces and identify them in the plug-in but beware as this will lead to a pretty complex set of shading objects so for the lighting applications or Suncast (if you want to see the effect thermally in analysis) this could lead to very long simulation times if not out of memory errors.

Hope it works out for you but really you want to keep things as simple as you can.

Phil

[luanaepb]

Hello,

Phill, there's another point I would like to clarify with R Dias' question.

For example, if I want to represent an overhang, I can simply define one planar surface to an external wall, with a material with opacity 100%. Is there any effect, for the sading calculation, if I set the overhang's opacity to a different value, like 50%?

Thanks!

[PCully]

Hi,

The single plane would be identified by our plug-in as a Shading Surface so again I believe it would ignore any transparency and treat it as fully opaque surface. I'm sure a few test simulations would confirm this for you (post back results if you do study this).

Phil

[luanaepb]

Hi Phill!

Thanks! I'll make some tests and I'll post here again!

[luanaepb]

Hi!

I've performed some simulation in order to test the shading opacity' sensitivity and I've got some results.

I've tested differents opacity values (10,25,50,75,100%) and I haven't verified great difference in the solar gain. In fact, there had some difference but I think it can be explained because each calculation is different from the other ( is this reasonable?)

Thanks!

Luana

[PCully]

As long as it was strictly controlled then the results should be consistent, it sounds like the changes you measured weren't related to the opacity of the shading device but other factors (did you re-identify the geometry each time?)

If interested further you could repeat the tests but keeping the opacity the same on the shading and check if you observe slight discrepancies again.

Small changes to the geometry that is identified by the plug-in would be my best guess for this.

Phil

[luanaepb]

Hi Phill,

I've changed my strategy a little bit! =)

This time, I've kept the rooms and I've imported only the shading elements. The results were exactly the same. So I think the shading opacity defined in Sketchup there's no effect in IES.

Thanks!

[volatile_ant]

One way around this is to create a room above or below the shade itself, tricking IES into thinking it is a skylight. From there you can change the opacity of the skylight glass. Make the other room surfaces holes (so they don't block any light) and you have a transparent/translucent shade.

Just be sure to run simulations at a higher quality level to calculate borrowed light.

Not a perfect solution, but it seems to work.

[bluebird5]

Suncast if you want to see the effect thermally in analysis this could lead to very long simulation times if not out of memory errors.