Photometric lights are much dimmer than corona lights?

[Jpjapers]

I have two lights. On the left is the corona light. on the right is a photometric light.
Both are using the same IES. Both are set to the same lumens and same colour temperature.

Why is the photometric light so much dimmer?
I need to be able to create a gobo projection effect so if theres a way i can do this with corona lights in absence of an actual projection slot on the corona light, that would be great.

Max 2022 - Corona 9.

[pokoy]

It could be that Max internal physical light doesn't take into account emission vs area distribution. when using directionality. I also remember Zap mentioning that light units in physical lights are wrong in some situations but have no further details unfortunately... not sure Max lights and Corona lights can really be compared 1:1 with the same values.

[Jpjapers]

It could be that Max internal physical light doesn't take into account emission vs area distribution. when using directionality. I also remember Zap mentioning that light units in physical lights are wrong in some situations but have no further details unfortunately... not sure Max lights and Corona lights can really be compared 1:1 with the same values.

The corona light has no directionality applied as the directionality does not work when using an IES file. I agree though the photometric lighting units seem to be exhibiting some non-physical behaviour.
It would be SO much easier if corona lights finally had a projection map slot given its been a feature request for literally ten years at this point. I get that its fake, but its also impossible to achieve a gobo with a corona light even if you place a filter infront of it and use the correct IES for the lens of the light fixture.

They should be comparable though given that lumens is an absolute measure of light and theyre both using the same IES profile.

[Basshunter]

It would be SO much easier if corona lights finally had a projection map slot given its been a feature request for literally ten years at this point. I get that its fake, but its also impossible to achieve a gobo with a corona light even if you place a filter infront of it and use the correct IES for the lens of the light fixture.

As a person who works in the stage design field, I'd also wish Corona Lights had more features like the ability to use gobos and to simulate other types of stage lights out of the box. As you mentioned, the gobo feature has been requested many times for many years.

[Jpjapers]

Those look pretty cool. The fact that Unreal has such good support for gobos and stage lighting in general makes me think that i should start working towards moving some of my work into Unreal.

Theres gobo/Projection map requests here fairly frequently dating back to 2013.

[Basshunter]

Those look pretty cool. The fact that Unreal has such good support for gobos and stage lighting in general makes me think that i should start working towards moving some of my work into Unreal.

Yeah, definitely. That's my long-term goal.

[Aram Avetisyan]

This is possible to do with Corona. You need to use Photometric lights, have CoronaShadows enabled, optionally enable Area shadows, use Volume light effect, and control the intensity with Hotspot beam and its falloff, optionally also volume light settings, and you can also use the projection map with it.
Remember that Corona is targeted for photo-realistic and physically accurate rendering, fakes and effects are most probably possible to do with it, but you need to dig deeper than expected. And expect not perfect support of it (e.g. you need to right-click restart IR to see updates).

Some results attached.

Hope this helps.

[Aram Avetisyan]

I have two lights. On the left is the corona light. on the right is a photometric light.
Both are using the same IES. Both are set to the same lumens and same colour temperature.

Why is the photometric light so much dimmer?
I need to be able to create a gobo projection effect so if theres a way i can do this with corona lights in absence of an actual projection slot on the corona light, that would be great.

Max 2022 - Corona 9.

As for original topic: I would not recommend expecting any "physically correct" or analogous to CoronaLights results with Photometric lights with Corona settings (e.g. CoronaShadows, Area/soft shadows etc.)
Just increase the intensity until you see the desired effect.
Also note that with Photometric lights you need to almost always right-click restart the IR to see the updates.

[Jpjapers]

I have two lights. On the left is the corona light. on the right is a photometric light.
Both are using the same IES. Both are set to the same lumens and same colour temperature.

Why is the photometric light so much dimmer?
I need to be able to create a gobo projection effect so if theres a way i can do this with corona lights in absence of an actual projection slot on the corona light, that would be great.

Max 2022 - Corona 9.

As for original topic: I would not recommend expecting any "physically correct" or analogous to CoronaLights results with Photometric lights with Corona settings (e.g. CoronaShadows, Area/soft shadows etc.)
Just increase the intensity until you see the desired effect.
Also note that with Photometric lights you need to almost always right-click restart the IR to see the updates.

Ok thanks thats very useful to know

[Jpjapers]

Im not sure if this is a bug or a feature but photometric lights do not show up in volumetric materials unless they are set to photometric and have an IES file loaded.
Would be really great to get a projection map slot in corona lights (or a tutorial on how to set up gobos with corona lights) to solve all of these issues.

[Aram Avetisyan]

Here is the scene I created, you can take a look at the light properties and how things are set up.

Hope this helps.

[Jpjapers]

Here is the scene I created, you can take a look at the light properties and how things are set up.

Hope this helps.

This is not a gobo. A gobo is a pattern disc that filters the light into specific shapes. Youve set up a volumetric light environment effect.

https://en.wikipedia.org/wiki/Gobo_(lighting)

What youre proposing isnt really an answer to what we are talking about. This isnt a true volumetric effect nor does it work with gobos in the projection map slot. A gobo will affect the shape of the volumetric rays which unfortunately this doesnt do but putting a photometric light through a corona volume material DOES do. Its just that the intensity is then broken. Ive put in a feature request that explains more.

[Aram Avetisyan]

I need to be able to create a gobo projection effect so if theres a way i can do this with corona lights in absence of an actual projection slot on the corona light, that would be great.

This was your initial request, wasn't it?
It would be better if you were specific and detailed enough for what you wanted to achieve.

I have provided a way to create the colored volumetric effect from the video above, which you somewhat liked, and it seemed that was what you were going for.
The sent scene uses Photometric lights, which have option for projection map option.
Weren't you aware of it?

So, you can use standard lights, which have Projection map option, with Corona, with CoronaShadows.
You can get somewhat close results with IES and real volumetric material, but remember that there will be issue with render times.

See the image attached, is this what you are looking for?
If yes, use the Projection map option advanced effects menu of Standard lights.

[Jpjapers]

I need to be able to create a gobo projection effect so if theres a way i can do this with corona lights in absence of an actual projection slot on the corona light, that would be great.

This was your initial request, wasn't it?
It would be better if you were specific and detailed enough for what you wanted to achieve.

I have provided a way to create the colored volumetric effect from the video above, which you somewhat liked, and it seemed that was what you were going for.
The sent scene uses Photometric lights, which have option for projection map option.
Weren't you aware of it?

So, you can use standard lights, which have Projection map option, with Corona, with CoronaShadows.
You can get somewhat close results with IES and real volumetric material, but remember that there will be issue with render times.

See the image attached, is this what you are looking for?
If yes, use the Projection map option advanced effects menu of Standard lights.

My request was for gobos in projection map slots yes but specifically with corona lights because of the issues with both the standard light (no IES Support, no physical light units) and the photometric light (Intensity is broken when used with corona shadows). I believe the use of the term gobo is specific and detailed enough because its a very specific lighting term. Theres not a better way of saying it other than gobos in corona lights but apologies if it was unclear.

Yes i was aware of the projection map slot in the standard light and its doing a sort of OK job for maybe some sort of quick previz but its far from good in my opinion. It doesnt provide a good solution because of the issue i originally noted where you have to eyeball the light intensity but it also doesnt support IES.

So the choice i see currently is either;

Fake volumetrics on a standard light with a post-process effect and you have to eyeball the intensity using the scene units multipler. You also cant apply an IES which is integral for stage lighting. No supplemental GI from the volume rays.

Or

Real volumetrics with a photometric light and an IES where you still end up needing to eyeball the intensity of a photometric light because despite using physical units, its currently not physically accurate when using corona shadows. You also have to play with the tiling of the projection map to get it to display the right size for the 'aperture' of the IES.

I don't mind the render time penalty for accurate-looking atmospherics with stage lighting. I just would like to be able to do them with a corona light where i can be certain of the physically correct light intensity as per my specifications, and can be certain that the volumetric ray effect will match the projection pattern. The best option in my opinion would be native support for projection maps in the corona lights which removes the need of compounding fake upon fake upon fake to achieve a filtered shadow on a volumetric ray that is somewhat accurate. There are requests for this exact feature dating back to 2013 but i have created other request today to reiterate the need.

I have attached a quick render demonstrating why none of the currently available solutions are accurate or provide all of the features required for any kind of physically based results with gobos and volumetric rays.

[Basshunter]

Jpjapers original request was for a gobo projection with Corona lights.

I seconded his request and added that this had been requested many times for many years now. Also mentioned how great it would be to have specific options to create stage lights which is part of my everyday job. These options include gobos, focus, falloff, etc, like in Blender's video.

With current Corona light is not even possible to recreate a proper moving head beam effect.