Lightwave 2020.0.2 - Physical Sky Tip

Marty3DGuru

Member
I remember people having an issue with the new setup of environment and physical sky, particularly with the ugly black nadir that they didn't like with using the physical sky.

Here is the solution to that issue.
 

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Marty3DGuru

Member
Do not use any global properties, just use the environment panel to set your lights up. They need to be in the correct order of backdrop first and then physical sky underneath in 2nd on the list. If you order them the other way you will only see the backdrop and get no physical sky properties or effect.

Control the sun setting/appearance with physical sky settings. Then attach this to the distant light in the scene using the same panel so you can move the sun position with the directional rotation.

The distant light can be tweaked for sun position and intensity of the sun spot on your reflective surfaces using the light intensity of the distant light. Use the physical sky settings to create light strength overall and ambience.
 
Thats brilliant Marty, thanks for sharing. That black fade has always been a problem for me.

Out of interest, why use the Distant Light type and not the SunLight type?

Let me add - I always find using the SunLight along with Physical Sky backdrop super confusing... as in I never know which controls are the master controls, the light or the physical sky panel.
 

Marty3DGuru

Member
Hi.

To be honest you could light the whole scene with one environment light and nothing else. Have no global backdrop effects, use the environment light panel as above image, to add a backdrop gradient first and then use a physical sky second and it would light the scene.

Having the two lights in the scene with the distant one as well, allows you to link this distant light to the environment light that is using the physical sky so you can better position the location and elevation. It is far easier and quicker to tweak than using the Hosek settings to achieve same thing. Notice if you have one environment light in the scene, the azimuth elevation options are available to tweak position and height. If you add a distant light but in the physical sky settings for the environment light, link item to itself the options for azimuth/elevation become greyed out. However when you link the physical sky from environment light to the distant light the options are available but don't seem to change anything, that is because it is expected that you would just adjust heading and pitch of light from the normal transform gizmo.

As far as your question why use distant light type as distant and not as sunlight type. This is to give you flexibility. The addition of distant light, not only allows you to tweak position a bit easier but the reflections themselves. This second light allows you to either use a physical sky type reflection or you could set your own reflection colour and make different looks. Think of the second light, the distant one, as a tweak to the reflection colour and intensity of your highlights in the scene without affecting the overall ambience the physical sky is giving you.

So to keep things simple. Environment light for overall light ambience, a second distant light for reflection/highlight intensity tweaks or mood looks. If you felt your environment ambience was nice but your specular highlights needed a boost, a second distant light allows you to keep the nice look of your environmnet and boost up your highlights or dial down the highlights as needed or blend in some extra colour.

With the second distant light then, you could of course make it a physical hosek or just as a standard distant light type in settings. This will affect the specular look of the sun in the reflections for more dramatic look or just to add some personal tweaks.
 
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Thats really helpful.

I actually often use two environment lights referencing the same global backdrop (usually an HDRI). Often I find the background image looks properly exposed but my object might look slightly over or under. So I use my 1st environment light with visible to camera on, but diffuse and specular off as my backdrop light - it obviously has no effect on the model. And then the 2nd environment light I have visible to camera off but affect diffuse and specular are on to light the model. Then by adjusting the 2nd light I can tweak the lighting on my model to more "correctly" match my background. Or vice versa... sometimes when I feel the model looks great I will tweak the exposure on the environment a bit.

Just thought Id mention it in case its ever useful to anyone.
 

Marty3DGuru

Member
Yeah, that's a good tip for sure. I think sometimes as users, people can feel like certain apsects are confusing or awkward but in some ways it is to provide greater flexibility of options.

Cheers.
 

lertola2

skeptic
Thanks for this thread. It has cleared up some confusing things for me. There is one basic thing, which you mentioned above, that I want to make more explicit because I did not understand it until today.

Its the Use Global checkbox at the bottom of the Light Properties / Light Type = Environment panel. Prior to today I did not understand that this control was here and what it did. Also I did not understand that Lightwave 2020 requires that there be an active environment light for the environment to be visible. Unlike lightwave 2015 where you just add environments to the Effects Backdrop panel.

environment_light_info2.jpg

In the past I have had problems opening LW2020 scenes not created by me and being very frustrated that trying to adjust the backdrop did not change anything. Sometimes I would recreate the scene from scratch to get the backdrop working. I think its confusing to have these controls in two places but now I understand whats going on. I do see that this is all explained in the manual. But I still mostly use LW2015 so I don’t have a lot of experience with the details of LW2020.
 
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Marty3DGuru

Member
It did seem a little confusing at first for sure, what to do for the best.

There are other options too. Still with using no global properties at all , just use the environment light panel, then add through the shader properties panel for reflections/refractions to use raytrace/ raytrace and spherical map etc.., even though you might not be using an HDR to light the scene or for a backdrop.
 
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