Hi guys, it's me again with a new render for you, and some problems to solve.
As you can see, I'm going on with experimentation in kray. This time is an old scene I made in lw time re-interpreting the famous work of Alex Roman: nothing new, but a good start point for common problems in archviz. Unfortunately lw/kray crashed after some attempts, so I've lost the settings for this scene, now I'm trying to replicate the same look.
Anyway, this is the render before the crash, with a fast pp just to complete the mood:
- actually there is no light under the small black table, but you can see there is some light leak. There are other leaks on the chairs, I can see that testing this scene: this happens if I put a 'N' value from 500 and over. Why is that?
- Keep in mind that the ball is 3mm thick simil-plexiglass (not luminous, but with fresnel translucency), and has a 100mm spherical light inside. Any advice when using a light inside an object? Because I tryed to exclude the object from light but without success... In lw engine does work. maybe is there a header/foot cmd?
- I had some problems using glass for the window because of the alpha (no dielectric this time, but a fresnel glass with fresnel 12), so for the render I've hidden the layer. But I need some suggestions to keep the reflections, and not exclude the glass because I like the overall effect.
- recurse: i tried recurse 100 in the foot cmd, but as you can see in the preview, it become completely red...
Thank you as always.
Some test, N value, light leaks etc...
Some test, N value, light leaks etc...
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Janusz Biela
- Posts: 3265
- Joined: Mon Mar 13, 2006 10:39 am
- Location: Finland
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Re: Some test, N value, light leaks etc...
This is very basic scene but it needs some knowledge:
- recurse has nothing to do with light of course scene is brighter when put over 20-30. But keep simple 10-12 maximum
- You got error because you put light inside lamp - photons have problems goes through the and after that rest scene - keep simple: use Lumi.
- windows glass ALWAYS put in separate layer and use exclusion from GI and shadows (windows has no effects in renders - it is only reflection and transparency with colour - so better just exclude them)
- do not try get effect directly from render - it is impossible
To make you happy I post some original renders (without post process) from Alex. Scenes are very simple (really!) but he use very complicate post process in AE and very good camera track.
Please notice errors in renders (splotches, light leaks)
- recurse has nothing to do with light of course scene is brighter when put over 20-30. But keep simple 10-12 maximum
- You got error because you put light inside lamp - photons have problems goes through the and after that rest scene - keep simple: use Lumi.
- windows glass ALWAYS put in separate layer and use exclusion from GI and shadows (windows has no effects in renders - it is only reflection and transparency with colour - so better just exclude them)
- do not try get effect directly from render - it is impossible
To make you happy I post some original renders (without post process) from Alex. Scenes are very simple (really!) but he use very complicate post process in AE and very good camera track.
Please notice errors in renders (splotches, light leaks)
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Re: Some test, N value, light leaks etc...
Hi Janusz, thank you as always for your answers.
So, I moved the light outside but behind the object, but the problem is still there: the leak goes away only if I set the lamp translucency = 0, this fix the problem with light leak and general splotches and the render looks perfect. In your experience, is it better to avoid translucency for objects? You know, sometimes I need a particular effect or sometimes is just a strange random request by the client that is a pain to fix in pp.
My problem with lumi poly is that for me they are really good for general/big illumination or fill light, but with specific light source can be tricky to get the desired effect. There is no way to exclude an object from light like lw does? What if I need to use a photometric/spherical/area light behind or inside an object but exclude the object from the light, or just because is too near and the light burns the colors? Example, sometimes, for fabric lamps, I make a fake shading solution with textures and luminosity maps, then I put inside (or really near) the light, and exclude the object, so it looks like it's the real emitter but for the render it's not, so is fast etc... is there a solution?
Now I'm trying with a lumi sphere around the source, hidden from camera/rays with 'Unseen by rays casts light' on, and it works, but this needs some workaround with luminosity power and color temperature because lumi poly don't give me much control.
Anyway, I perfectly understand what you mean, regarding the try to fix everything direct in the render... In my experience sometimes it's impossibile and a waste of time, but sometimes it helps to find creative solutions and learn to fix other future problems, so for me can be a good way to test alternative ways of work (if I'm not under a dead line of course!
)
Every time a look at Alex Roman's work (and not only him) it's obvious that the visual and composition skills are way important than pure 3d raw skills, and for this job, unless you are just a 'modeling man' it's what makes the difference. And of course pp skills are huge benefit of the creative process, it's what can make a 'so and so' render, become an awesome render
So, I moved the light outside but behind the object, but the problem is still there: the leak goes away only if I set the lamp translucency = 0, this fix the problem with light leak and general splotches and the render looks perfect. In your experience, is it better to avoid translucency for objects? You know, sometimes I need a particular effect or sometimes is just a strange random request by the client that is a pain to fix in pp.
My problem with lumi poly is that for me they are really good for general/big illumination or fill light, but with specific light source can be tricky to get the desired effect. There is no way to exclude an object from light like lw does? What if I need to use a photometric/spherical/area light behind or inside an object but exclude the object from the light, or just because is too near and the light burns the colors? Example, sometimes, for fabric lamps, I make a fake shading solution with textures and luminosity maps, then I put inside (or really near) the light, and exclude the object, so it looks like it's the real emitter but for the render it's not, so is fast etc... is there a solution?
Now I'm trying with a lumi sphere around the source, hidden from camera/rays with 'Unseen by rays casts light' on, and it works, but this needs some workaround with luminosity power and color temperature because lumi poly don't give me much control.
Anyway, I perfectly understand what you mean, regarding the try to fix everything direct in the render... In my experience sometimes it's impossibile and a waste of time, but sometimes it helps to find creative solutions and learn to fix other future problems, so for me can be a good way to test alternative ways of work (if I'm not under a dead line of course!
)Every time a look at Alex Roman's work (and not only him) it's obvious that the visual and composition skills are way important than pure 3d raw skills, and for this job, unless you are just a 'modeling man' it's what makes the difference. And of course pp skills are huge benefit of the creative process, it's what can make a 'so and so' render, become an awesome render
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Janusz Biela
- Posts: 3265
- Joined: Mon Mar 13, 2006 10:39 am
- Location: Finland
- Contact:
Re: Some test, N value, light leaks etc...
ok then You make me curious by this scene because it is second or third time at the forum...so in free time will make it.
About technical aspects in render: keep simple, no tricks, Luminescence maximum 200% - if is not enough then spherical Light outside. Outside light can be from background city texture (luminescence).
Scene is very, very simple (more important is post process for this render...because is strong and complicate - this also I will start on forum as new topic). You can notice extra green light from right site of scene - it is visible also in armchair reflection (I think he flipped horizontal frames for this view).
Generally three lights: from outside can be LW Background grey/blue colour, Lamp on the desk and this extra from right side).
About technical aspects in render: keep simple, no tricks, Luminescence maximum 200% - if is not enough then spherical Light outside. Outside light can be from background city texture (luminescence).
Scene is very, very simple (more important is post process for this render...because is strong and complicate - this also I will start on forum as new topic). You can notice extra green light from right site of scene - it is visible also in armchair reflection (I think he flipped horizontal frames for this view).
Generally three lights: from outside can be LW Background grey/blue colour, Lamp on the desk and this extra from right side).
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Re: Some test, N value, light leaks etc...
Yes, for sure it's a strong pp that make the deal with this images. PP a part, I can do something really similar in lw but not in kray, so for me is a good benchmark to work on and learn kray.
Ok, this is the super basic setup, all reset, just a basic tonemap, so I can better understand one piece at time how lumi poly works in kray (now I have the full license). For me coming from the lw default engine it's clear now that is a bit different way to setup the scenes. As I can see the color of light seems more saturated in lw, but I find the color temperature, in example very warm light like 3500k, less orange/yellow in kray.
This are the very basic settings:
Outside: just a pitch gradient from dark blue to light blue on texture environment, 200% opacity.
Inside:
1st image (the darker one) just a lumi poly sphere 200% luminous, 50cm diameter on top of the table. Hidden by camera and hidden by rays, but 'cast light' in kray
2nd image (the one with the lumi poly hidden from camera but reflected in the window) same settings, but not hidden by rays.
3rd image no lumi poly, no balls, just the lw spherical light 40%, 100mm size, 1m inv sq distance.
Glass is fresnel, 10 value, with no shadows and no radiosity.
It's strange because i find the lumi poly very weak, I'm probably making a mistake but I don't know where.
Ok, this is the super basic setup, all reset, just a basic tonemap, so I can better understand one piece at time how lumi poly works in kray (now I have the full license). For me coming from the lw default engine it's clear now that is a bit different way to setup the scenes. As I can see the color of light seems more saturated in lw, but I find the color temperature, in example very warm light like 3500k, less orange/yellow in kray.
This are the very basic settings:
Outside: just a pitch gradient from dark blue to light blue on texture environment, 200% opacity.
Inside:
1st image (the darker one) just a lumi poly sphere 200% luminous, 50cm diameter on top of the table. Hidden by camera and hidden by rays, but 'cast light' in kray
2nd image (the one with the lumi poly hidden from camera but reflected in the window) same settings, but not hidden by rays.
3rd image no lumi poly, no balls, just the lw spherical light 40%, 100mm size, 1m inv sq distance.
Glass is fresnel, 10 value, with no shadows and no radiosity.
It's strange because i find the lumi poly very weak, I'm probably making a mistake but I don't know where.
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Janusz Biela
- Posts: 3265
- Joined: Mon Mar 13, 2006 10:39 am
- Location: Finland
- Contact:
Re: Some test, N value, light leaks etc...
Of course lumi will be too soft with level maximum 200% but if you will extend more then you will start have problem with noise in reflection blur - simply support it by Area Light or Spherical Light.
Keep this tone map and if is still too dark then increase gamma (but not much)
It my opinion is the best mix of tone mapping which keep colours and GI in very good level.
Do not try receive same effect directly from render! It is impossible. Render must be clean: without noise, perfect AA even if is a bit over bright but not burn with light!. It will be very good material for post processing. Good post and DoF will push render to next level.
Keep this tone map and if is still too dark then increase gamma (but not much)
It my opinion is the best mix of tone mapping which keep colours and GI in very good level.
Do not try receive same effect directly from render! It is impossible. Render must be clean: without noise, perfect AA even if is a bit over bright but not burn with light!. It will be very good material for post processing. Good post and DoF will push render to next level.