GI Light Bounces?

S

SA9R

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I have a scene with the camera inside of a hollow column. The lighting should have the light fade out way at the end of the column. I would think that adjusting the number of GI bounces would extend the light into the column, but it has no visual effect. Quite different from the days of FPrime's GI. How can this be done in the latest version of Lightwave?


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The number of GI bounces is not a factor in increasing the energy of light to travel further.

That would be down to the intensity of the light as measured in lumens. So increasing the light's lux value will extend the reach of the light, but will also increase the brightness of the scene.

To maintain the brightness and just extend the reach you'd have to use the nodes to adjust the light's intensity falloff distance.
 
Yup...lighting isn´t bounce reflected towards the end of the tunnel, only sides, so amount of bounces has no effect, had you a capping in the beginning and end of the tunnel, it would be different.
 
Ok, nodes. Thanks. There it is. That's where they "hid" the "Range" parameter that used to be in the Light Properties panel.

Had to filter for anything "Light" in the Nodes Panel and then add the Light Falloff node from Functions. Double-click the node and change its value to 25m in the property window that pops up. And then connect the Light Falloff type to Illumination Color of the Light Shader node (Not intuitive... color?? Intensity!). And back in the Light Properties panel, the Intensity Falloff type had to be set to Off, otherwise it threw off the lighting equation.

I think the numerous light falloff types and range parameters could have been left in the Light Properties panel. The simple was complicated in this case. At least it can be done, but UX should could be better by adding nodes but not taking those other two parameters out of the Light Properties panel. Hmm...

 
SA9R said:
Ok, nodes. Thanks. There it is. That's where they "hid" the "Range" parameter that used to be in the Light Properties panel.

Had to filter for anything "Light" in the Nodes Panel and then add the Light Falloff node from Functions. Double-click the node and change its value to 25m in the property window that pops up. And then connect the Light Falloff type to Illumination Color of the Light Shader node (Not intuitive... color?? Intensity!). And back in the Light Properties panel, the Intensity Falloff type had to be set to Off, otherwise it threw off the lighting equation.

I think the numerous light falloff types and range parameters could have been left in the Light Properties panel. The simple was complicated in this case. At least it can be done, but UX should could be better by adding nodes but not taking those other two parameters out of the Light Properties panel. Hmm...

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with 2018 and up..the lightwave team started on a wrong direction that was different from their previous philosophy of accessing things easy.

you can also see this in other ui element channels...such as texture channels for surfaces.
 
prometheus said:
with 2018 and up..the lightwave team started on a wrong direction that was different from their previous philosophy of accessing things easy.

you can also see this in other ui element channels...such as texture channels for surfaces.
Click to expand...
Yeah I think it was a matter of just too much work to have the "T" in all the those places. Who knows. :) It did turn off a lot of people to not have those "T's" everywhere.
 
Tim Parsons said:
Yeah I think it was a matter of just too much work to have the "T" in all the those places. Who knows. :) It did turn off a lot of people to not have those "T's" everywhere.
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Seems the developers had an idea that everything should be as much nodal editing as possible, and thus skipped keeping the philosophy of easy to setup which has been lightwave´s strength for such a longtime, and the implementation isn´t even good.
The principle idea of that transcends on to volume items, where you have to enter nodally to set a hypertexture, they could have made it much smoother and easier.

Blenders texture insert, just click on the yellow dot for the base color, choose image texture, it is now setup already with a nodal connection, this we should have in Lightwave.

The only equal way to have it already setup, would be to actually use the older standard layer texture surface material type, then convert it to principled in Lightwave.
 
After the final render, adjusting the white and black points in Image Controls is helpful. Similar to Maxwell's camera exposure, though less flexible since it is done after the render with the high floating point image data in LW.
 
As well as increasing the GI bounces, you'd also need to increase the ray recursion limit (depending on which LW version you're using).

But the much more efficient way would be to use the falloff in the lights.
The reason they removed it, is because it's not PBR. They wanted to ensure that users didn't mess up the PBR... which is great for most things, but actually sometimes it's nice to be able to go beyond what the renderer decides for us :)
 
lardbros said:
As well as increasing the GI bounces, you'd also need to increase the ray recursion limit (depending on which LW version you're using).

But the much more efficient way would be to use the falloff in the lights.
The reason they removed it, is because it's not PBR. They wanted to ensure that users didn't mess up the PBR... which is great for most things, but actually sometimes it's nice to be able to go beyond what the renderer decides for us :)
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Removed what?
 
lardbros said:
As well as increasing the GI bounces, you'd also need to increase the ray recursion limit (on on which LW version you're using).
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I'm not sure if you're making this statement in relation to the light falloff issue in the OP, but if you are, then this information that you've provided is incorrect.

Neither the GI bounces, nor ray recursion limit settings affect how the lights in a scene falloff.
 
Shabazzy said:
I'm not sure if you're making this statement in relation to the light falloff issue in the OP, but if you are, then this information that you've provided is incorrect.

Neither the GI bounces, nor ray recursion limit settings affect how the lights in a scene falloff.
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I was replying to the initial post. He didn't see the light moving upwards in the tunnel, upon increasing the GI bounces, but to see that, I'm sure the ray recursions would need to be increased along with the GI bounces.

As you say, light fall off has nothing to do with the GI light bounces or the ray recursion.
 
lardbros said:
I was replying to the initial post. He didn't see the light moving upwards in the tunnel, upon increasing the GI bounces, but to see that, I'm sure the ray recursions would need to be increased along with the GI bounces.
Click to expand...

Hmm. I think I understand where you're coming from and I'm trying to picture in my mind how these settings could achieve what you propose given that ray recursion limit affects the reflections in a scene in addition to the diffuse bounces setting.

I think to achieve what you propose, you'd have to increase the light's intensity or have additional lighting. I doubt just increasing the RRL and diffuse bounces setting alone would do it.
 
Shabazzy said:
Hmm. I think I understand where you're coming from and I'm trying to picture in my mind how these settings could achieve what you propose given that ray recursion limit affects the reflections in a scene in addition to the diffuse bounces setting.

I think to achieve what you propose, you'd have to increase the light's intensity or have additional lighting. I doubt just increasing the RRL and diffuse bounces setting alone would do it.
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It's not really what I personally propose. I'm answering the OP's original post.
He wasn't seeing the GI light 'climbing' up the tunnel as he increased the light bounces, so I suggested why :)

I did a quick test in LW 2020 and what I said works, if you increase the diffuse bounces, the light creeps up the tunnel, until 6 bounces... then no difference, until you start increasing the ray recursion as well. LW 2020 is limited to 32 bounces i think, and the further you increase this, the brighter it gets at the base, so it's not ideal.

In LW 2020, you also have a reflection and refraction recursion limit, so you could limit it this way.
Of course, the best solution is to use a light, with no falloff :)
 
It's also good I did the test as I've also found a bug :) Related to GI bounces and the roughness of a surface in 2020.
Will be saving these scene files and reporting as a bug if LW ever gets back to development :)
 
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