OTOY Forums

Was there a change in how IES lights behave in 2.1

Before i was able to rotate them in studio (create a light disk) and the IES light would change direction based on rotating the prop in studio. Now it make no difference, what i do in studio. the light always seem to point strait down.

Thanks

Nick

Update / Edit 2015 07 25:

In the current version of OcDS2.23 the different projection modes are named differently in the pulldown menu as in OctaneRender standalone.
This can result in some confusion for those users who are trying to follow the instructions in the OctaneRender standalone manual in which it is recommended to use Mesh UV projection for IES lights.

It seems what is called Mesh UV projection in OctaneRender standalone is called UVW projection in the OcDS plugin.
What is called XYZ to UVW Projection in OctaneRender standalone is called linear projection in the OcDS plugin.

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Update/ Edit 2015 06 22:

birdovous figured it out and shared the result:

birdovous wrote:I think I nailed it

These are the settings that seem to work for me in the latest version of the OcDS plugin (see screenshot).

Projection has to be set to Linear and then Coordinate Space can be set to Normal Space (IES Lights)

Additonal information:
- use a small plane as light emitter
- orient the normals of the plane down to the floor if you want the light streaks visible on a wall as in the IES preview image.

- In OR standalone the Mesh UV projection seems to yield to result that is closest to the IES preview image.

compare OR standalone manual:

http://render.otoy.com/manuals/Standalo ... age_id=901

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Original post:

alaman64 wrote:Was there a change in how IES lights behave in 2.1

Before i was able to rotate them in studio (create a light disk) and the IES light would change direction based on rotating the prop in studio. Now it make no difference, what i do in studio. the light always seem to point strait down.

Thanks

Nick

Short Answer:

In order to link the IES light direction with the object normal direction you need to activate

"Projection" - "Coordinate Space" - "Normal Space (IES Lights)"

Once this setting is activated rotating the light emitting object will also rotate the IES light direction in relation to the normal direction of your object.

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The longer version:

@ rotation

I can observe the same behavior.
Rotating a prop does not (anymore?) seem to have an effect of the orientation of the IES light without changing additional settings.
This may have worked similar with the Orientation settings in the past though.

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@ Orientation settings were replaced with new options

There was not only a name change to "Emission pattern" but also basic IES functionality seems to have changed in one of the 2.x standalone updates.

In the past IES lights had Orientation settings included to change the direction of the light.
Those seem to have been exchanged with another functionality called Projection.
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Update / Edit:

New IES Settings "hidden" under Projection and Coordinate Space

It seems there are additional options hidden for IES lights under "Projection"

Depending on which Projection you select there appears an additional pulldown menu for "Coordinate Space"

There is a setting for "Normal Space (IES Lights)"
When you activate this in theory now the IES lights should point in the direction of the normals of the object you are using.

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Imager Settings - Exposure - Highlight Compression

With 2.15 some Imager settings were updated as well that may be useful when working with IES lights.
Instead of F-stop, Iso and Exposure there is no only one overall "Exposure" setting remaining.

Use "Exposure" to adjust the overall light level of the scene.
Only use the "Power" level of your light emitters for small adjustments relative to other scene lights.

Use "Highlight Compression" to get rid of burnt out highlights in your scene.
Highlight = extremly bright white area.

Very useful setting and a great addition. Thanks Otoy!
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Need to do a bit more testing later.
I am now able to create cicle like emitting patterns.

But I still have not figured out the settings to make the light rays appear as cones exactly as in the IES preview...

Thanks for the detailed explanation, it helped me figure out the problem.

I needed to have a small spot light point at an object and no where else with no light leakage. I was able to accomplish this see image below, and was able to change the size of the spot light. Very important if you want to highlight someone eyes only.

You can do this using the spherical projection and scale.

Let me know if you have any questions.

Nick

btw, even it is a little more complicated to set up now, there should be another advantage: since ies orientation is solely controlled by the texture projection, it is most probably no longer needed to skip mesh collapsing (for final and animations) when the scene contains ies lights; i have not yet completely tested it, but will probably add a config switch (in the config text file) to either skip or don't skip collapsing when ies lights are detected.

this means if you also keep any light emitting object at 100% scale (because of power changes when a scaled mesh is collapsed), the only thing left not applicable for collapsing would be instances...

I dig up this old thread.
It seems still the same issues are confusing users.

Any information either by fellow forum users or official amins, staff, plugin or standalone developers would be very much appreciated.

What was the official intended way how we are supposed to combine IES light presets with projection so that the result looks like in the preview images of the IES lights?


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In theory:

In order to link the IES light direction with the object normal direction you need to activate

"Projection" - "Coordinate Space" - "Normal Space (IES Lights)"

Once this setting is activated rotating the light emitting object will also rotate the IES light direction in relation to the normal direction of your object.

An example of such settings:

IES Perspective Projection Normal Space (IES Lights)

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In practice:

- I now tried around more than an hour again and still have not found the proper settings to actually make the IES lights appear similar like in the preview image.

Which is the official and recommend projection mode to be used with IES lights?

Which exact settings need to be used in combination with the IES presets included in OcDS to make them appear in the scene exactly like in the preview images?

Example:
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Update/Edit:
Now obsolete speculation removed.

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I added the test scene. One file for OcDS and one file for the standalone.

So anyone interested in figuring this out, creating a step by step guide or sharing results has a quick way to get started.

I think I nailed it

These are the settings that seem to work for me in the latest version of the OcDS plugin (see screenshot).

Projection has to be set to Linear and then Coordinate Space can be set to Normal Space (IES Lights)

birdovous wrote:I think I nailed it

These are the settings that seem to work for me in the latest version of the OcDS plugin (see screenshot).

Projection has to be set to Linear and then Coordinate Space can be set to Normal Space (IES Lights)

Yay you did it!!! Thanks a lot for helping and sharing your results!

I noticed that you used a smaller plane and this also helped a lot to make the effects more visible!

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For the first test with linear projection I made a smaller plane and lined it up with the wall so the normals of the plane face away from the wall.
The effect I am looking for with IES 19 is that visible streaks have their original at the light source.
At the moment it looks like some wave like circles are cast at a distance.

So there still seemed one detail missing.

I now oriented the light emitting plane so the normal actually points down to the floor.
Now it looks pretty much like in the IES preview image.
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The last step now would be to actually lower the opacity of the light emitting plane to zero so it is invisible and only the light effect remains.

I still wanted to figure out the proper settings for OR standalone so I kept experimenting.


After exporting the OcDS scene to standalone I noticed some differences.

What I knew before was that the OcDS plugin and OR standalone seem to have different projection options:

In OR standalone you find:
- Mesh Projection.
- XYZ to UVW Projection.

In the OcDS plugin you find

- UVW Projection
- linear Projection

.

The linear projection found in OcDS is translated to a XYZ to UVW projection without any XYZ transformation node.
I then tried around further in OR standalone and consulted again with the OR standalone manual

http://render.otoy.com/manuals/Standalo ... age_id=901


I than choose the "UV Mesh" projection that seems to be missing in the OcDS plugin projection options:
To me it seems like the Mesh UV projection does yield the result that is most close to the IES preview image.


In OcDS the Mesh UV projection is currently called UVW projection.
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Different Projection Names used in OR standalone and the OcDS plugin:

It seems what is called Mesh UV projection in OctaneRender standalone is called UVW projection in the OcDS plugin.
What is called XYZ to UVW Projection in OctaneRender standalone is called linear projection in the OcDS plugin.

It may be after all that Projection in the OcDS plugin works the same as in OR standalone but the settings are just named differently.

Sometimes DAZ Studio limits how some options are implemented in the OcDS plugin.
I will write a PM to ask t_3 if in that case it is possible to use the same names as in OR standalone.

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Update / Edit:
Allready got a reply from t_3.
The different naming can be considered a bug.
There were some limitations how node names were generated that now can be updated with the current version.

It seems what is called Mesh UV projection in OctaneRender standalone is called UVW projection in the OcDS plugin.
What is called XYZ to UVW Projection in OctaneRender standalone is called linear projection in the OcDS plugin.

Fixed in the next release.

Paul