Shadow range analysis question

Replies to This Discussion

Permalink Reply by Abraham Yezioro on September 27, 2015 at 1:00am

Esteban,
Specularity is not supposed to be a result of the shadows range. Is the image taken from a baked geometry? If so, this is a Rhino setting.
-A.

Permalink Reply by Esteban Agüero on September 27, 2015 at 6:50am

Hello Abraham, 

I'm sorry maybe I misunderstood the concepts. I'm running a Image based simulation like Mostapha shows in this tutorial. 

Permalink Reply by Abraham Yezioro on September 27, 2015 at 7:21am

Ahhh!!

I was thinking you were using the LB_sunlightHoursAnalysis component. Now i see you are doing this in HB+Radiance. So my suggestion is to check the materials you are using and reduce the specularity or give a 0 value at all. Also check the reflectance of the material. There is a chance this is affecting the simulation.

-A.

Permalink Reply by Esteban Agüero on September 27, 2015 at 7:32am

I tried setting manually the material with this Colour picker tool for radiance

This is my white opaque material

Specularity = 0 

Roughness = 0.2 

Reflectance = 1 (I can't manage this parameter)

void plastic identifier
0
0
5 1 1 1 0 0.2

Permalink Reply by Esteban Agüero on September 27, 2015 at 7:37am

Is there another way to reduce this shinny effect?

Permalink Reply by Abraham Yezioro on September 27, 2015 at 8:07am

Are you using the HB_radOpaqueMaterial component. There you can set as you wish and need.

Uploading your file can be helpful.

-A.

Permalink Reply by Chris Mackey on September 27, 2015 at 3:02pm

Thanks as always, Abraham, for being the ever-present sentinel of the forums.

Esteban,
I believe that this is a property of nearly all materials when light shines into a corner or onto a set of perpendicular planar surfaces. It is not the result of the specularity of the material but just the fact that you just get a lot of light bouncing back and forth between the two perpendicular surfaces as they get closer to intersecting one another regardless of whether the light is reflected specularly or diffusely. My intuition tells me that decreasing the overall reflectance of the material might diminish this effect but I don't think that you will be able to get rid off f it without the simulation no longer being "physics-based."

Mostapha is the master of Honeybee radiance and he might have more insight into this.

-Chris

Permalink Reply by Mostapha Sadeghipour Roudsari on October 7, 2015 at 8:53pm

That material is 100% reflective! That's why you get all that light spots. Try something less reflective:

void plastic identifier
0
0
5 .5 .5 .5 0 0.2

Permalink Reply by Sarith Subramaniam on September 27, 2015 at 6:50pm

I am not sure if the issue that you are facing is related to specularity or exposure....here is what happens if you change the exposure on a Radiance image.

e = 0

e= -1

e=-2

e= -3

e = -4

Setting exposure values is a "post-processing" thing done to improve the display of the image on a device or photograph. So, your analysis will still be physically based. I think towards the end of his video Mostapha talks about how the exposure values can be set through Honeybee....

Permalink Reply by Abraham Yezioro on September 27, 2015 at 9:36pm

And that's why is always good to upload the example file.

Agree that this doesn't seem to be exposure issue. Still think this is a material definition one.

-A.