31
Gallery / Quartz crystals
« on: 2014-03-27, 13:59:45 »
All corona raw baby...
2024-05-12, 19:24:05
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32
Work in Progress/Tests / Candelabro
« on: 2014-03-25, 04:26:46 »
A chandelier.
Wich render option suit best this kind of scene?. Any advice would greatly improve this wip.
Wich render option suit best this kind of scene?. Any advice would greatly improve this wip.
33
[Max] Tutorials & Guides / Shadow catcher solution, (matte) workaround in Corona A6.
« on: 2014-03-20, 17:08:58 »
Just came with this idea for a shadow matte o shadow catcher.
1.- First render your scene as usual (i use an hdri and a crane model i'm working on).
2.- Assign a default white material to all geometries that needs to catch shadows ( in my case... just a plane).
3.- In Corona render settings assign a material override with a black corona material to all scene assets except the geometries you want to catch shadows.
4.- Add a CShading_shadows render element. As i noticed, ou can compose the "inverted" shadow pass (Ctrl+i with the layer selected in photoshop) later in "multiply mode" over the beauty pass.
1.- First render your scene as usual (i use an hdri and a crane model i'm working on).
2.- Assign a default white material to all geometries that needs to catch shadows ( in my case... just a plane).
3.- In Corona render settings assign a material override with a black corona material to all scene assets except the geometries you want to catch shadows.
4.- Add a CShading_shadows render element. As i noticed, ou can compose the "inverted" shadow pass (Ctrl+i with the layer selected in photoshop) later in "multiply mode" over the beauty pass.
35
[Max] Tutorials & Guides / Realistically fake refractive dispersion caustics
« on: 2014-03-18, 04:43:16 »
I just want to share an aproach to Realistically "FAKE" dispersion in a refractive material.
Since Corona A5 does not have a dispersion setting and i needed to have a diamond, came up with this idea.
The post render tab in corona allows to save green, red or blue channel of a render, so in order to fake diamond refraction one just need to find the refrection index of diamond for determined color.
This page shows the index of refraction as a curve and can show you the IOR for determined wavelength. http://refractiveindex.info/?shelf=3d&book=crystals&page=diamond
I use diamond specs but it could be applied to any refractive material.
So we need to find the aprox equivalence between wavelength and RGB color... (remember this is a fake, but a very informed one... XD). This place has something one could use http://academo.org/demos/wavelength-to-colour-relationship/
For red (255,0,0) = 658nm that gives us a IOR of: 2.40975
For green (0,255,0) = 510nm that gives us a IOR of: 2.43024
For blue (0,0,255) = 440nm that gives us a IOR of: 2.44856
So we create 3 materials each with diferent IOR as stated, then render just saving the channel for that IOR color.For example, apply the first material with IOR 2.40975 and save the image but just the red channel (set appropiate numbers in post tab of corona red:1 green:0 blue:0).
Do that for each Material saving the correspondent color channel for that ior.
The next step is open the 3 images in photoshop as layers and set the layer as Linear dodge (ADD) to get the composite of the 3 wavelengths.
And there you have it. A really convincent fake dispersion for a diamond render or any refractive material.
Here can have the test scene used in max 2014 and corona A5 and the composite in photoshop, and the final image as shown.
By the way the scene is illuminated just with CoronaSun and sky only. But i Guess works with hdrs or custom illumination as well.
Since Corona A5 does not have a dispersion setting and i needed to have a diamond, came up with this idea.
The post render tab in corona allows to save green, red or blue channel of a render, so in order to fake diamond refraction one just need to find the refrection index of diamond for determined color.
This page shows the index of refraction as a curve and can show you the IOR for determined wavelength. http://refractiveindex.info/?shelf=3d&book=crystals&page=diamond
I use diamond specs but it could be applied to any refractive material.
So we need to find the aprox equivalence between wavelength and RGB color... (remember this is a fake, but a very informed one... XD). This place has something one could use http://academo.org/demos/wavelength-to-colour-relationship/
For red (255,0,0) = 658nm that gives us a IOR of: 2.40975
For green (0,255,0) = 510nm that gives us a IOR of: 2.43024
For blue (0,0,255) = 440nm that gives us a IOR of: 2.44856
So we create 3 materials each with diferent IOR as stated, then render just saving the channel for that IOR color.For example, apply the first material with IOR 2.40975 and save the image but just the red channel (set appropiate numbers in post tab of corona red:1 green:0 blue:0).
Do that for each Material saving the correspondent color channel for that ior.
The next step is open the 3 images in photoshop as layers and set the layer as Linear dodge (ADD) to get the composite of the 3 wavelengths.
And there you have it. A really convincent fake dispersion for a diamond render or any refractive material.
Here can have the test scene used in max 2014 and corona A5 and the composite in photoshop, and the final image as shown.
By the way the scene is illuminated just with CoronaSun and sky only. But i Guess works with hdrs or custom illumination as well.
36
[Max] General Discussion / The albedo question.
« on: 2014-03-16, 00:05:37 »
I guys, i have spent few days reading the forum but i still can't answer a simple question.
The corona wiki states that a cause of poor performance in rendering is caused by this:
"Too high walls albedo in an interior scene. Albedo is the percentage of energy a material reflects, and in Corona is the sum of diffuse, reflective, refractive, and translucent components. In reality almost no materials have near-white albedos, and using white albedo (for example 255-white diffuse color) in rendering gives very unrealistic and slow results, and cannot be correctly rendered with an unbiased renderer. Try keeping albedos of all your main scene objects under RGB 180, and get whiter walls by brightening light sources.
There is a table around that list common albedos for tipical materials.
It says that snow (for example) has an albedo of between 40 to 85 (depending on snow).
The question itching in the back of my head is:
Where is the albedo in the material editor?...
The diffuse section includes a LEVEL (0-1), an rgb color and the posibility of load a texture, same for reflection and refraction.
If the albedo of a material is 0.4 do i put level to 0.4 in diffuse and leave reflection and refraction at 0 so the sum is that 0.4?
Or is the rgb that sums that way?... what if i put a texture?... and if that color in texture are way beyond "1! like an exr or hdr?...
And what happen if the material is an emitter one?... (by the way can't find the light material in A5, is present only in dailys?).
Hope some one can share wisdom.
The corona wiki states that a cause of poor performance in rendering is caused by this:
"Too high walls albedo in an interior scene. Albedo is the percentage of energy a material reflects, and in Corona is the sum of diffuse, reflective, refractive, and translucent components. In reality almost no materials have near-white albedos, and using white albedo (for example 255-white diffuse color) in rendering gives very unrealistic and slow results, and cannot be correctly rendered with an unbiased renderer. Try keeping albedos of all your main scene objects under RGB 180, and get whiter walls by brightening light sources.
There is a table around that list common albedos for tipical materials.
It says that snow (for example) has an albedo of between 40 to 85 (depending on snow).
The question itching in the back of my head is:
Where is the albedo in the material editor?...
The diffuse section includes a LEVEL (0-1), an rgb color and the posibility of load a texture, same for reflection and refraction.
If the albedo of a material is 0.4 do i put level to 0.4 in diffuse and leave reflection and refraction at 0 so the sum is that 0.4?
Or is the rgb that sums that way?... what if i put a texture?... and if that color in texture are way beyond "1! like an exr or hdr?...
And what happen if the material is an emitter one?... (by the way can't find the light material in A5, is present only in dailys?).
Hope some one can share wisdom.
37
[Max] General Discussion / Info on fireflies supressión
« on: 2014-03-15, 19:16:59 »
I just read this in the RandomControl forum respect to fireflies supression.
http://randomcontrol.com/blog/?p=1666
http://randomcontrol.com/blog/?p=1666
39
[Max] Resolved Feature Requests / CoronaMoon
« on: 2014-03-09, 22:11:32 »
Just an idea... to CoronaSun.
And environment map that mimics a night sky with stars and moon.
Actually one could select a place on globe and a date and generate some kind of exr texture to put in the environmental slot.
For shure there is plenty of places on the net where one could pick information for that.
Off course a slider to set the amount of stars and moon size. I've seen that maps on cell apps.
It would be a totally awesome add for Corona.
... or just add a greater than 90 degree slider to the corona sun model to mimic nigth sky.
Just my 2 pesos cuates...
And environment map that mimics a night sky with stars and moon.
Actually one could select a place on globe and a date and generate some kind of exr texture to put in the environmental slot.
For shure there is plenty of places on the net where one could pick information for that.
Off course a slider to set the amount of stars and moon size. I've seen that maps on cell apps.
It would be a totally awesome add for Corona.
... or just add a greater than 90 degree slider to the corona sun model to mimic nigth sky.
Just my 2 pesos cuates...
40
Work in Progress/Tests / Night shot
« on: 2014-03-08, 20:44:05 »
I havent seen any night shots in the gallery so i converted one industrial scene i have using the scripts in the forum from Vray.
Pretty much out of the box settings on corona, one hdri in environmental slot and a couple of mesh emitters on the lamps.
19 hours so far.
The hdri shows as some small brigth dots on the back. Some kind of bug?. I lower the hdri to 0.01 (from 1 as default) to mimic night illumination from sky.
Any suggestions would be very appreciated.
Pretty much out of the box settings on corona, one hdri in environmental slot and a couple of mesh emitters on the lamps.
19 hours so far.
The hdri shows as some small brigth dots on the back. Some kind of bug?. I lower the hdri to 0.01 (from 1 as default) to mimic night illumination from sky.
Any suggestions would be very appreciated.