In order to fully understand the possible render output in Vray using various environment settings such as the combination of Vray Sun and Vray Sky, Domelight+ HDRI and Vray Environment + HDRI, I made a simple rendering experimentation that highlights different parameters or settings which generally affect the tonality and atmosphere of the rendered image output.
During the test render experimentation, I enabled the material override and set the water pool to Can be Overridden . I also added a Sphere model inside the scene with silver polished material in order to see the reflection of the sky.
For Vray Sun and Sky System, I set up a basic scene in default setting and lit it a couple of different ways, (enabling and disabling) Vray sun, background, and GI (Skylight). For Vray dome light with HDRI texture, a comparative test render was made using default setting and optimized setting. For Vray Environment with HDRI texture, the test render will highlights the possible output when render in optimized setting using HDRI as the light source and Vray sun as an additional light source.
1. Vray Sun and Sky System
2. Dome light+ HDRI
3. Vray Environment+ HDRI
4. Vray Sun Sky Model
1. Vray Sun (Summarized settings)
2. Dome light+ HDRI (Summarized settings)
3. Vray Environment + HDRI (Summarized settings)
pachasnack.com Sun and Sky System
In Vray default setting, Vray Sun and Vray Sky are special features which are provided by the Vray Render engine. When set in default setting, notice the sunlight is enabled. If you go to Vray Asset Editor> Settings> Environment> Background, you can see that the default background is set to Vray Sky or technically the Vray Sun (Vray sunlight). Under Environment Overrides, the GI Skylight is technically turn-off in default settings. However, when you turn on the GI Skylight option and choose the Vray sky as the light source, the render result will be similar to Vray default settings. In comparison with Domelight and Vray Environment settings, the shadow use to appear sharper when rendered using Vray Sun and sky system.
| Vray Sun|
Settings (default) and show a similar render output, which produces clearer environment. Here, when enabling the GI skylight with Vray sky as the light source and Vray sun is turned on at the same time, the render result is similar to default settings. This particular render output goes the same in Setting with a slight difference in terms of its background.
Settings and show a similar render output. Enabling the GI skylight with Vray sky as the light source while the Vray Sun is turned off doesnt produce such brighter environment. Here, the light power using GI skylight with Vray sky as the light source does not produce a brighter environment as compared with the Vray sun when turned on. The Vray Sky as the background image manage to illuminate in the material of the 3-D object. In terms of atmosphere, Setting shows almost the same result on settings and but with different background.
Setting shows that turning off the Vray sun and GI sky light (which means there is no light source) makes the model illuminate to darker environment, but still manages to render the background with clear visibility, when turned on.
Setting shows that when using both Vray sun and GI skylight with no light source, the environment becomes warmer, cloudy or hazy. This atmosphere goes the same in Setting with a slight difference in terms of its background appearance.
Setting shows that increasing the value of GI skylight with Vray sky as the light source while the Vray sun is disabled produce a brighter illumination of materials.
| Vray Sun settings|
Using Vray for SketchUp, when loading a Dome light+ HDRI in default setting, the render result will be darker in nature (See image / Setting A). Thus, optimizing the Dome light settings is important in order to produce a suitable environment in relation to HDRI map. (See image / Setting B). In order to set-up the Dome light: click the Dome light icon and place it in your SketchUp scene. To change the parameters for Dome light follow the procedures: under Vray Asset Editor> go to Lights> click the Vray Dome light> under Light dome, you can see two main parameters (Main and Options). Follow the parameters set-up I made for this test render experiment (See image Dome light Setting). The shadow in Dome light+ HDRI setting appears to be smoother than Vray sun setting. This can be illustrated in test render sample (see image / Setting B and Setting B). Using Dome light setting, the lights come from HDRI map as direct light, and all kinds of effects like shadows, reflection, etc will be apparent.
| Dome light|
| Dome light settings|
pachasnack.com Environment + HDRI
In Dome light, adjusting the intensity will generally affect both the background and the light at the same time. The advantage of using Vray Environment than Dome light is that you can use different maps for both lighting and background while at the same time, adjusting the intensity separately by multipliers. Optimizing the Vray Environment is important in order to produce a suitable environment to your scene. Enabling Vray sun while GI skylight is turned on (with optimized setting) is not necessary, since you dont need to have two light sources in your scene. Having two light sources in one scene will just increase the render time.
| Vray Environment|
| Vray Environment Settings|
pachasnack.com Sun Sky model
Hosek et al. The VRaySky procedural texture will be generated based on the Hosek et al. method.
Preetham et al. The VRaySky procedural texture will be generated based on the Preetham et al. method.
CIE Clear The VRaySky procedural texture will be generated based on the CIE method for clear sky.
CIE Overcast The VRaySky procedural texture will be generated based on the CIE method for cloudy sky.
| Vray Sun Sky Model|
| Sun Sky Model Options|
SOURCE: Click Here
PARAMETERS:pachasnack.com Sun (Default setting)
Vray Sun and Sky system, ensure a faster render than Domelight and Vray Environment. This render setting is the very basic of Vray sun environment.
| VRAY SUN (default)|
pachasnack.com light+ HDRI
| Vray Sun (settings)|
The Vray Dome light is a really quick way to get clean results if you can't use irradiance maps which is typical in Vray Environment setting. The V-Ray dome light does the importance sampling which gives you a better shadows, quicker and cleaner render than Vray Environment.
| DOMELIGHT HDRI|
| Dome light HDRI (settings)|
pachasnack.com Environment + HDRI
On the other hand, Vray Environment setting offers a more flexible option as compare to Dome light setting. Here, you can adjust the intensity of the light source and the visibility of the background (both in HDRI map) separately using multiplier. Although, this is a more tedious work as compared to Dome light setting from which the intensity of the light source and background can be adjusted all at once, I prefer this set-up because you have the liberty to adjust the background and the light source separately, based on your preferred settings.
| VRAY ENVIRONMENT HDRI|
| Vray Environment (settings)|