Perfect. Thank you!
Nick
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Technical Discussion » edges from knife tool
- lor
- 292 posts
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Technical Discussion » edges from knife tool
- lor
- 292 posts
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Hi there
Is there a way to select only the newly created edges from a knife modeling operation?
NB
Is there a way to select only the newly created edges from a knife modeling operation?
NB
Houdini Lounge » what is with the new Principled Shader?
- lor
- 292 posts
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Wow. After all those years getting the mantra surface shader into decent shape, suddenly I have a shader that requires me to look in multiple tabs to find all the elements that are affecting a channel.
Why are texture maps on their own tab? Each texture map should be nestled with it's parametric controls, otherwise how can I see all the parts of my channel at a glance? This is terrible for troubleshooting.
Boooo.
Nick
Why are texture maps on their own tab? Each texture map should be nestled with it's parametric controls, otherwise how can I see all the parts of my channel at a glance? This is terrible for troubleshooting.
Boooo.
Nick
Technical Discussion » OpenSubdiv Motion blur bug?
- lor
- 292 posts
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Technical Discussion » OpenSubdiv Motion blur bug?
- lor
- 292 posts
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Can anyone confirm this as a bug?
Houdini 16.0.600
-Add a sphere,
-turn on render polys as subdivision(Mantra)
-change subdivision style to OpenSubdiv Catmull-Clark
-add a mantra rop
-turn on allow motion blur
-set geo time samples to 2
The render goes bananas. Looks like a bug with OpenSubdiv.
Nick
Houdini 16.0.600
-Add a sphere,
-turn on render polys as subdivision(Mantra)
-change subdivision style to OpenSubdiv Catmull-Clark
-add a mantra rop
-turn on allow motion blur
-set geo time samples to 2
The render goes bananas. Looks like a bug with OpenSubdiv.
Nick
Edited by lor - 2017年6月17日 11:22:26
Houdini Lounge » What is up with light "Exposure"?
- lor
- 292 posts
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Houdini Lounge » Physical Camera
- lor
- 292 posts
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With the big advances in Houdini lighting/shading since v9, there remains a big gap, and that's a physical camera.
More and more artists & TDs are demanding better camera control analogous to real cameras, especially good exposure control. (note that turning a light up and down is not equivalent to camera exposure control). It would be so great if CG lighters could speak the same language as the camera crew.
To this end, please +1 if you support the development of a physical camera that supports the following (or add your comments if you think something should be added to./removed from the list) These in addition to the current camera controls:
-shutter or disk (shutter speed / shutter angle) for still or moving camera. that affects exposure and motion blur
-F-stop that affects exposure and DOF
-T-stop that affects exposure and DOF
-horizontal and vertical lens shift
-ND filters (equivalent to global light intensity control without CT shift)
-ISO
-White balance
-natural vignetting
Nick
More and more artists & TDs are demanding better camera control analogous to real cameras, especially good exposure control. (note that turning a light up and down is not equivalent to camera exposure control). It would be so great if CG lighters could speak the same language as the camera crew.
To this end, please +1 if you support the development of a physical camera that supports the following (or add your comments if you think something should be added to./removed from the list) These in addition to the current camera controls:
-shutter or disk (shutter speed / shutter angle) for still or moving camera. that affects exposure and motion blur
-F-stop that affects exposure and DOF
-T-stop that affects exposure and DOF
-horizontal and vertical lens shift
-ND filters (equivalent to global light intensity control without CT shift)
-ISO
-White balance
-natural vignetting
Nick
Houdini Lounge » What is up with light "Exposure"?
- lor
- 292 posts
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Andy58
In my experience, lighters care more about creating a pleasing image and matching lights than actual light intensities. And the option of stopping up and down lights with ‘exposure’ is predictable and much appreciated. People saying light inensities shouldn't go above 1.0 is something from the days preceding linear workflow. It's not something I've heard or seen done in years.
Just curious, since you seem so focused on real world parameters – what unit for light intensity do you propose?
Andy
Andy, I agree, exposure stops are a great idea and also that the pleasing image is the more important goal. Problem is, this parameter doesn't do exposure. As for lights not above 1, major studios in town have CG supervisors directing junior lighters to do this. So it's still rampant, unfortunately.
The major block here seems to be that people think I'm against an exposure control, which I'm not. I'd love one. There isn't one in Houdini yet. what they've done is added a second light intensity control and improperly named it exposure. We can fiddle with it as much as you want, it will never change the exposure of the image.
Nick
Houdini Lounge » What is up with light "Exposure"?
- lor
- 292 posts
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mestela
*shrug*
Tell every lighting department in every studio to use absolute intensity rather than exposure. Once they've all agreed, then you can demand sidefx change their knob.
That's not the point. The point is that this knob doesn't do exposure, yet is called exposure.
N
Houdini Lounge » What is up with light "Exposure"?
- lor
- 292 posts
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Hello ladies & gents,
I don't disagree that exposure , Fstop, Tstop, shutterspeed/angle should be a part of our toolset. Absolutely they should. But they should do what they do in a camera not something vaguely similar that can be roughly explained through convoluted logic. This control is not analogous to F-stop or Tstop, which affect all lights. This is a per light intensity control.
We have two things on set related to light. Lights and a camera. Lights put out a certain quality/quantity of light. Cameras receive it. Light intensity controls the quality/quantity of light coming OUT of particular light source. (This is what the new houdini light “exposure” control does). Camera exposure affects the light coming IN to the camera. the new houdini light “exposure” control does not do this. It's pretty simple. The exposure control doesn't control exposure.
We need a physical camera with functional exposure control.
For an example of a great physical camera, have a look at VRay.
In Houdini, the shutter“time” and fstop controls have no effect on exposure. There is, effectively no exposure control in houdini, making light intensity values arbitrary. So I can see why people are asking for exposure control, but it would be nice if that was actual exposure control, not a secondary exponential light intensity control, per light.
@Andy58, thanks for that quote. It is my opinion that lighting people SHOULD have to use huge values like 10,000. In this way they can begin wrapping their heads around the real nature of light. That's what real light intensity actually is! It is essential we break away from the old thinking that lights need to be at or below 1.0 int. Artists who start to get a handle on how friggin bright lights actually are tend to do better work and use their tools better, IMO.
Nick
I don't disagree that exposure , Fstop, Tstop, shutterspeed/angle should be a part of our toolset. Absolutely they should. But they should do what they do in a camera not something vaguely similar that can be roughly explained through convoluted logic. This control is not analogous to F-stop or Tstop, which affect all lights. This is a per light intensity control.
We have two things on set related to light. Lights and a camera. Lights put out a certain quality/quantity of light. Cameras receive it. Light intensity controls the quality/quantity of light coming OUT of particular light source. (This is what the new houdini light “exposure” control does). Camera exposure affects the light coming IN to the camera. the new houdini light “exposure” control does not do this. It's pretty simple. The exposure control doesn't control exposure.
We need a physical camera with functional exposure control.
For an example of a great physical camera, have a look at VRay.
In Houdini, the shutter“time” and fstop controls have no effect on exposure. There is, effectively no exposure control in houdini, making light intensity values arbitrary. So I can see why people are asking for exposure control, but it would be nice if that was actual exposure control, not a secondary exponential light intensity control, per light.
@Andy58, thanks for that quote. It is my opinion that lighting people SHOULD have to use huge values like 10,000. In this way they can begin wrapping their heads around the real nature of light. That's what real light intensity actually is! It is essential we break away from the old thinking that lights need to be at or below 1.0 int. Artists who start to get a handle on how friggin bright lights actually are tend to do better work and use their tools better, IMO.
Nick
Houdini Lounge » What is up with light "Exposure"?
- lor
- 292 posts
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Hi Babaj,
To be clear, when we say “exposure” in photography, it is short for “exposure to light” or even longer “how long the film/CCD is exposed to light” or “how much light reaches the exposure medium through variable aperture and shutterspeed/angle.” One can't really say that aperture and shutterspeed does not control exposure, as they are the primary exposure controls. Exposure is a global control that affects all light reaching the exposure medium. It still doesn't make sense to rename individual light intensity to exposure.
For further clarity, the light “exposure” control only controls the light intensity of a single light, not of all lights in the scene, which might make more sense.
I guess film ISO doesn't really belong there as it's sensitivity rather than exposure control and generally used when we reach the limits of our exposure controls.
Certainly not all renders are photoreal, but that doesn't mean we can take the word “colour” which is well known and use it to describe displacement or take the word “rotation” to mean “translation”. And no, this is not an exaggeration.
Taking the word “exposure” which is a set of universally well-known camera controls and using it to describe individual light intensity is…kinda weird.
Nick
To be clear, when we say “exposure” in photography, it is short for “exposure to light” or even longer “how long the film/CCD is exposed to light” or “how much light reaches the exposure medium through variable aperture and shutterspeed/angle.” One can't really say that aperture and shutterspeed does not control exposure, as they are the primary exposure controls. Exposure is a global control that affects all light reaching the exposure medium. It still doesn't make sense to rename individual light intensity to exposure.
For further clarity, the light “exposure” control only controls the light intensity of a single light, not of all lights in the scene, which might make more sense.
I guess film ISO doesn't really belong there as it's sensitivity rather than exposure control and generally used when we reach the limits of our exposure controls.
Certainly not all renders are photoreal, but that doesn't mean we can take the word “colour” which is well known and use it to describe displacement or take the word “rotation” to mean “translation”. And no, this is not an exaggeration.
Taking the word “exposure” which is a set of universally well-known camera controls and using it to describe individual light intensity is…kinda weird.
Nick
Edited by lor - 2016年9月19日 15:05:13
Houdini Lounge » What is up with light "Exposure"?
- lor
- 292 posts
- Offline
Good Day SESI community,
Are you an artists or TD with photographic/cinematographic training who has been confused by the addition of the “exposure” control into the light interface?
After trying to wrap my head around what the he## an “exposure” control (which is specifically and exclusively a series of camera settings) is doing on a light, I contacted SESI support. The response was that, the control name is
What the???
They say:
Aside from the fact that this is fundamentally false, did anyone here ask for a second light intensity control called “exposure” to be added to a light? It's like having two sets of transform coordinates, but one is exponential.
What this control does is exponentially control light intensity. So now we have two light intensity controls, one that moves light intensity linearly and one that moves it exponentially. This isn't terrible(except for its name), but I'm curious why a lighter can't simply type in higher values like 10,000 or 10,000,000, which are totally natural light intensity values.
I suspect it may have something to do with the widely held belief that lighting artists should never turn their light intensity values above 1.0, which is actually quite ludicrous when you consider the actual light intensity values that exist in nature. It feels like this extra control was added to crank up light intensity in a way that lets artists pretend they're still keeping light intensity values below 1.0. If true, this is actually harmful to the development of lighting artists understanding of the true nature of light. Lights should often be cranked way up. They're really, really bright.
Now, I don't have an objection to a second exponential light intensity slider per se…but two things really should happen here. First of all, it should NOT be named “exposure” (more on that in a moment) and second, the actual intensity value that results should be displayed. Right now, if you turn a light up to 2 and then crank the “exposure”, you think your light intensity value is still 2, but it is not. The real value is hidden from you. Not so easy to do real light ratio calculations when the true light intensity value is hidden.
Why It Should Not Be Called Exposure
Exposure is a well-known global value in photography which is very exact. It refers to how much light reaches the exposure medium. Exposure can not be controlled on a per-light basis. Exposure can be controlled at the camera using a number of methods including:
1. Aperture-Fstop or Tstop
The aperture is a variable hole in the lens housing that limits the amount of light from all light sources getting through. Change in aperture varies depth of field. The light “exposure” control does not do either of these things.
2. shutter speed/angle 1/xx or degrees
Shutter speed (still) or angle (moving) varies the amount of time the exposure medium is exposed to all light sources. Change in shutterspeed/angle varies motion blur. The light “exposure” control does not do either of these things.
3. filmstock/ISO various known values
Filmstock/ISO varies the sensitivity of the exposure medium to all light sources. Varying the filmstock/ISO changes the grain quality of the captured image. The light “exposure” control does not do either of these things.
4. ND filters
Neutral Density Filters placed in front of the lens change the quantity of light entering the lens from all light sources. This is the most like the light “exposure” control, except that it acts on all light sources, not just one.
So If It's Not Exposure, What Is It?
Well it's in a scale of -10 to 10, which doesn't correspond with any established exposure control. Going out of default range very far can really wig it out too.
It is simply exponential light intensity control and should be named appropriately. Furthermore the total light intensity from this control should be displayed.
Who Cares?
Anyone with photography or cinematography training, and everyone once SESI develops a physical camera and has to implement real exposure calculations, at which time they will be obliged to rename this control anyway, causing further confusion later.
It makes no sense to co-opt the name of such a well known set of camera controls (exposure) to change something which is clearly and absolutely not exposure. This causes nothing but confusion, especially among photographers.
I teach lighting. At my school, where we also teach photography/cinematography, we have to teach that there is a light control in Houdini called “exposure” which is nothing like the exposure controls we teach in photography class. We have to teach that it really just changes individual light intensity more radically than the regular light intensity control and that it does not affect exposure in any way. This is the only way students with photography training can make any sense of the control.
I believe it is essential to keep parameters sensibly named. And although SESI states they think “exposure” is intuitive, for photographers, it is exactly the opposite. It is further my opinion that any CG photographer ( we call them lighting artists) should be well trained in camera. The cg camera is, after all, supposed to be a virtual analogue of the real camera. We are virtual photographers.
I look forward to opinions on this and, hopefully, decent alternative names to this control.
Next topic: Lets get a physical camera under development!! All in favor?
If you made it this far into my rant, thank you for taking the time, I apologize for taking up so much of your day.
Nick
Are you an artists or TD with photographic/cinematographic training who has been confused by the addition of the “exposure” control into the light interface?
After trying to wrap my head around what the he## an “exposure” control (which is specifically and exclusively a series of camera settings) is doing on a light, I contacted SESI support. The response was that, the control name is
“based on the effect the control has, disregarding the fact that it doesn't exist in the physical world.”
What the???
They say:
“While real world lights obviously don't have a concept of exposure, the effect of changing exposure on all CG lights in your scene is the same as changing it globally on your camera or render, so there's a natural correspondence. It appears to be intuitive to most artists and is an often requested feature, so I'm afraid it's here to stay.”
Aside from the fact that this is fundamentally false, did anyone here ask for a second light intensity control called “exposure” to be added to a light? It's like having two sets of transform coordinates, but one is exponential.
What this control does is exponentially control light intensity. So now we have two light intensity controls, one that moves light intensity linearly and one that moves it exponentially. This isn't terrible(except for its name), but I'm curious why a lighter can't simply type in higher values like 10,000 or 10,000,000, which are totally natural light intensity values.
I suspect it may have something to do with the widely held belief that lighting artists should never turn their light intensity values above 1.0, which is actually quite ludicrous when you consider the actual light intensity values that exist in nature. It feels like this extra control was added to crank up light intensity in a way that lets artists pretend they're still keeping light intensity values below 1.0. If true, this is actually harmful to the development of lighting artists understanding of the true nature of light. Lights should often be cranked way up. They're really, really bright.
Now, I don't have an objection to a second exponential light intensity slider per se…but two things really should happen here. First of all, it should NOT be named “exposure” (more on that in a moment) and second, the actual intensity value that results should be displayed. Right now, if you turn a light up to 2 and then crank the “exposure”, you think your light intensity value is still 2, but it is not. The real value is hidden from you. Not so easy to do real light ratio calculations when the true light intensity value is hidden.
Why It Should Not Be Called Exposure
Exposure is a well-known global value in photography which is very exact. It refers to how much light reaches the exposure medium. Exposure can not be controlled on a per-light basis. Exposure can be controlled at the camera using a number of methods including:
1. Aperture-Fstop or Tstop
The aperture is a variable hole in the lens housing that limits the amount of light from all light sources getting through. Change in aperture varies depth of field. The light “exposure” control does not do either of these things.
2. shutter speed/angle 1/xx or degrees
Shutter speed (still) or angle (moving) varies the amount of time the exposure medium is exposed to all light sources. Change in shutterspeed/angle varies motion blur. The light “exposure” control does not do either of these things.
3. filmstock/ISO various known values
Filmstock/ISO varies the sensitivity of the exposure medium to all light sources. Varying the filmstock/ISO changes the grain quality of the captured image. The light “exposure” control does not do either of these things.
4. ND filters
Neutral Density Filters placed in front of the lens change the quantity of light entering the lens from all light sources. This is the most like the light “exposure” control, except that it acts on all light sources, not just one.
So If It's Not Exposure, What Is It?
Well it's in a scale of -10 to 10, which doesn't correspond with any established exposure control. Going out of default range very far can really wig it out too.
It is simply exponential light intensity control and should be named appropriately. Furthermore the total light intensity from this control should be displayed.
Who Cares?
Anyone with photography or cinematography training, and everyone once SESI develops a physical camera and has to implement real exposure calculations, at which time they will be obliged to rename this control anyway, causing further confusion later.
It makes no sense to co-opt the name of such a well known set of camera controls (exposure) to change something which is clearly and absolutely not exposure. This causes nothing but confusion, especially among photographers.
I teach lighting. At my school, where we also teach photography/cinematography, we have to teach that there is a light control in Houdini called “exposure” which is nothing like the exposure controls we teach in photography class. We have to teach that it really just changes individual light intensity more radically than the regular light intensity control and that it does not affect exposure in any way. This is the only way students with photography training can make any sense of the control.
I believe it is essential to keep parameters sensibly named. And although SESI states they think “exposure” is intuitive, for photographers, it is exactly the opposite. It is further my opinion that any CG photographer ( we call them lighting artists) should be well trained in camera. The cg camera is, after all, supposed to be a virtual analogue of the real camera. We are virtual photographers.
I look forward to opinions on this and, hopefully, decent alternative names to this control.
Next topic: Lets get a physical camera under development!! All in favor?
If you made it this far into my rant, thank you for taking the time, I apologize for taking up so much of your day.
Nick
Technical Discussion » Irradiance caching
- lor
- 292 posts
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Technical Discussion » Irradiance caching
- lor
- 292 posts
- Offline
Howdy,
I'd like to store and re-use a single indirect lighting solution across a bunch of frames to speed up renders. It's a great technique used in other renderers. I assumed “Irradiance caching” would do this, but I can't find a workflow. Any advice?
Thanks
Nick
I'd like to store and re-use a single indirect lighting solution across a bunch of frames to speed up renders. It's a great technique used in other renderers. I assumed “Irradiance caching” would do this, but I can't find a workflow. Any advice?
Thanks
Nick
Work in Progress » H15 Baking
- lor
- 292 posts
- Offline
Can the baketexture ROP be previewed in the renderview? This sure would speed up the workflow.
N
N
Houdini Lounge » Rendering in Houdini - A big call for discussion
- lor
- 292 posts
- Offline
Work in Progress » Student project. Rendered with Mantra.
- lor
- 292 posts
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Mantra is a beautiful, powerful and relatively simple tool with super powers under the hood. Here's what 9 students can do with it in 16 weeks:
https://vimeo.com/105397678 [vimeo.com]
https://vimeo.com/105397678 [vimeo.com]
Houdini Lounge » Kelvin Colour Temperature colour selection option
- lor
- 292 posts
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Houdini Lounge » Kelvin Colour Temperature colour selection option
- lor
- 292 posts
- Offline
Well sure, there are always work-arounds. The point is workflow. It's an obvious, much needed, valuable parameter that any modern renderer claiming to be physically-based should have and that, when absent, slows a lighting TD down.
Nick
Nick
Houdini Lounge » Kelvin Colour Temperature colour selection option
- lor
- 292 posts
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Good Day,
I'd like to make a case for adding Kelvin Colour Temperature to all lights in Houdini.
Since all incandescent light falls within the Kelvin colour temperature scale, and since most light sources are incandescent, it stands to reason that this extremely useful and valuable ability would be present in the Houdini lighting/shading system, especially as it is working toward physically based rendering.
I'd say easily 75% of the lighting I do could benefit from Kelvin CT as a colour selection method in Houdini. Currently, in order to find a Kelvin CT, I have my crew:
-Open Maya and add a VRay light
-Set the VRay light colour mode to Kelvin
-Enter the desired kelvin CT
-Switch the colour mode back to ‘colour"
-record the RGB and/or HSV values
-go back to Houdini and enter the rgb or hsv values for the desired CT.
Maya/VRay is quite an expensive and cumbersome Houdini plug-in just to find kelvin CT.
I have asked for this several times over the years. Not sure why such an obvious gap in the toolset has not yet been filled. Certainly most of the other relevant rendering tools have a Kelvin CT option.
If you would also like to see Kelvin CT added as a light colour option in Houdini, please add your +1 and let’s see if we can convince SideFX to throw some dev time there.
Nick
I'd like to make a case for adding Kelvin Colour Temperature to all lights in Houdini.
Since all incandescent light falls within the Kelvin colour temperature scale, and since most light sources are incandescent, it stands to reason that this extremely useful and valuable ability would be present in the Houdini lighting/shading system, especially as it is working toward physically based rendering.
I'd say easily 75% of the lighting I do could benefit from Kelvin CT as a colour selection method in Houdini. Currently, in order to find a Kelvin CT, I have my crew:
-Open Maya and add a VRay light
-Set the VRay light colour mode to Kelvin
-Enter the desired kelvin CT
-Switch the colour mode back to ‘colour"
-record the RGB and/or HSV values
-go back to Houdini and enter the rgb or hsv values for the desired CT.
Maya/VRay is quite an expensive and cumbersome Houdini plug-in just to find kelvin CT.
I have asked for this several times over the years. Not sure why such an obvious gap in the toolset has not yet been filled. Certainly most of the other relevant rendering tools have a Kelvin CT option.
If you would also like to see Kelvin CT added as a light colour option in Houdini, please add your +1 and let’s see if we can convince SideFX to throw some dev time there.
Nick
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