Search found 912 matches

Search found 912 matches
by galinette
Sun Jan 10, 2010 6:53 am
Forum: Indigo General Stuff
Topic: Cauchy law
Replies: 4
Views: 1119

Re: Cauchy law

The CIE 1931 colorimetry states that light between 360nm and 830nm has to be taken into account for human vision. Many implementations use a restricted 380-780nm range which is normally OK. But 400-700nm seems quite too narrow. Which range is used in the observer functions used by Indigo?

Etienne
by galinette
Sun Jan 10, 2010 3:10 am
Forum: Bugs and Requests
Topic: Incorrect rendering of glass object lying on diffuse ground
Replies: 9
Views: 1168

Re: Incorrect rendering of glass object lying on diffuse ground

Hello, Sorry for forgetting the Indigo version : 2.0.12 Exporter is notepad++... This is why I did not mention it! The nudge distance is the default one I guess, since I did not change it. So the distance (0.05) is much greater than nudge distance. I will try to force the nudge distance. I will also...
by galinette
Sun Jan 10, 2010 12:40 am
Forum: Materials
Topic: Coated glass from real measured spectral data
Replies: 28
Views: 11686

Re: Coated glass from real measured spectral data

For sodalime glass (ie glass used in all automotives and buidlings, including tinted glasses), n is given in the table below. The k coefficient depends on tint. Here it is given for average clear iron glass (Fe around 900ppm), which is the most common glass, on which you may see green tint on the si...
by galinette
Sun Jan 10, 2010 12:28 am
Forum: Materials
Topic: Green Glass Help
Replies: 13
Views: 3293

Re: Green Glass Help

Nice render. I may provide soon some "real" coated architecture glass models soon (check my new topic). These glasses are very difficult to physically reproduce if you do not have the data, but you have found some esthetic hacks to give good look. These glasses have surfacic spectrally dependant ref...
by galinette
Sun Jan 10, 2010 12:15 am
Forum: Indigo General Stuff
Topic: Cauchy law
Replies: 4
Views: 1119

Re: Cauchy law

Here is what you get when you find Cauchy coefficients for sodalime glass (glass used in all building and car windows), in the visible part of the spectrum:

A 1.510891234
B 0.00424672

Fit graph:
glass_ri.jpg
Refractive index of sodalime glass, and Cauchy fit in the visible region.
glass_ri.jpg (53.58 KiB) Viewed 1276 times
Etienne
by galinette
Sat Jan 09, 2010 11:56 pm
Forum: Indigo General Stuff
Topic: Cauchy law
Replies: 4
Views: 1119

Cauchy law

Dear all, The simplified Cauchy law for dielectrics is n = A+B/lambda² In the specular model, we have to provide IOR and CAUCHY_B_COEF. I suppose the latter corresponds to B. What is the relation between IOR and A? It could be IOR=A but in that case, that means the real average refractive index will...
by galinette
Sat Jan 09, 2010 11:01 pm
Forum: Bugs and Requests
Topic: Incorrect rendering of glass object lying on diffuse ground
Replies: 9
Views: 1168

Incorrect rendering of glass object lying on diffuse ground

Dear all, I am working on the following scene. I remarked some non-natural gray zones on some of the glass objects. test_glass.jpg I made some tests and I tried to render the exact same scene, but enlarged the blue diffuse square ground by 10x : from (-20,-20)-(20,20) to (-200,-200)-(200,200). And n...
by galinette
Sat Jan 09, 2010 10:45 pm
Forum: Bugs and Requests
Topic: [Bug] Indigo stops responding whith an incomplete matrix
Replies: 1
Views: 456

[Bug] Indigo stops responding whith an incomplete matrix

In my code I accidentally inserted an incomplete matrix such as this one in the model:

<rotation>
<matrix>
0.9396926207859 -0.3420201433256
0.3420201433256 0.9396926207859 0
0 0 1
</matrix>
</rotation>

When launching the render, Indigo went into a unresponding state

Etienne
by galinette
Sat Jan 09, 2010 1:47 pm
Forum: Materials
Topic: Coated glass from real measured spectral data
Replies: 28
Views: 11686

Re: Coated glass from real measured spectral data

Hi, Yes, there is definitely absorption, which is also spectroscopic... I have all the tabulated datas. You can find a picture here illustrating this: http://pt.saint-gobain-glass.com/newsletter/2008_files/out2008_04_home.html You can see the color & reflectance angle dependance quite well. This giv...
by galinette
Sat Jan 09, 2010 11:18 am
Forum: Materials
Topic: Coated glass from real measured spectral data
Replies: 28
Views: 11686

Coated glass from real measured spectral data

Dear all, I would like to simulate a coated glass material with following characteristics: - The medium of the glass has a given index of refraction (for instance 1.52). Deviation of light by refraction should work exactly as the specular material does. - But the reflectance/transmittance coefficien...
by galinette
Sat Jan 09, 2010 8:31 am
Forum: Indigo General Stuff
Topic: Trouble rendering dispersion_test
Replies: 2
Views: 932

Re: Trouble rendering dispersion_test

Dear all, I have figured it out... MLT was not enabled The metropolis flag is said to be "true" in the documentation, but the default infile.xml sets it to false in the current installer. So I thought it was enabled and it was not... Clearly this is the case where MLT shines. You should not put exam...
by galinette
Sat Jan 09, 2010 2:31 am
Forum: Indigo General Stuff
Topic: Trouble rendering dispersion_test
Replies: 2
Views: 932

Trouble rendering dispersion_test

Hi all, I am evaluating Indigo for rendering glass material images. When I render the "dispersion_test.igs" file, in 800x600 with 580 samples per pixel, I get a lot of bright coloured dots in the glass prism. I think this may be caused by multiple bounce light paths which are not well sampled. I get...
Search found 912 matches