How to Fine-tune your Lighting and Shadows on Sketchfab

Lighting settings, like post-processing settings, are an easy way to quickly make your model look its best. This article will cover the essentials of how to use the lighting settings in Sketchfab’s 3D Editor. For a more detailed look at lighting and shadows, check out the Help Center.

Lit vs. Shadeless

Lit mode is Sketchfab’s default rendering mode and is appropriate in most cases. When you upload a new model to Sketchfab, environmental lighting and environmental shadows are switched on by default.

Shadeless mode should be selected for models that have lighting information baked into their textures. For example:

• 3D scans, unless they have been processed to extract other information than base color map
• Scenes with lighting baked into the textures, e.g., hand-painted art and some cartoon scenes

If you select Shadeless rendering, adding real-time dynamic lights will become unavailable, but you will still be able to use the baked AO Ground Shadow. You may also use an Environment, but it will only affect the look of the background and not the lighting.

Environment

Environmental lighting is provided by a 360° high dynamic range image (HDRi) and is the most realistic form of lighting available in Sketchfab’s 3D Editor. Each environment in the Environment dropdown offers different 360° real-world lighting (intensity, color, and direction) and reflection conditions. Which of the options you select will depend on how each of the environments interacts with your model. Try out several to determine which you like the best. After some experimentation, you may come to rely on two or three of the environments throughout your portfolio because they work best with your art style and color palette.

If you want to import your own lighting environment, you’ll need to have a Pro membership or higher. Full directions for HDR or EXR import can be found in the Help Center.

Orientation, Brightness, and Shadow

By changing the lighting environment’s Orientation, you are rotating it around your model and changing which parts of the environment interact with which parts of your model. Some environments vary subtly and others vary more substantially in the lights and colors at different orientation points.

The Brightness slider controls how much light your scene receives from the environment. Higher values offer more brightness and light and lower values offer less.

Finally, the Shadow settings allow you to toggle on or off shadows cast by the environment. The light intensity controls the intensity of the dominant light of the environment (the sun, for instance, in outdoor environments). Lower intensity offers dim dominant lighting and dim shadows, while higher intensity provides stronger dominant lighting and stronger shadows. Shadow bias defines the distance between the object that’s casting the shadow and the shadow. In most cases, it should not be needed, but it can be helpful in situations where the light direction is very shallow, or where the bounding box is quite big compared to the objects that are casting shadows.

Lights

If you have chosen Lit rendering mode, the Lights section at the top of the Lighting tab lets you select up to three dynamic lights to illuminate your scene. These lights are great for drawing attention to particular parts of a scene or model or for artistic lighting setups. Environmental lighting is preferable for whole-scene lighting.

Our Help Center does an awesome job of explaining each of the Lights settings, so we’ll just cover some of the essentials here.

Moving lights into position

Moving lights into the correct positions can feel a little tricky sometimes. If you’re struggling to get the lights where you want them, reduce your Field of View to 0° in the general Scene settings. Then, navigate your model so that you are looking at front, side, and top views, pulling the arrows on each light until they are where you want them.

To select a particular light, just click on the light in the viewer or select it from the list of lights in the lights settings.

Also, keep in mind that position and direction do not affect lighting in the same way for every type of light. See below for more information on that.

Light selection

If you’re in a hurry or don’t want to play around with lighting settings, we have six great lighting presets that you can access by clicking on “Load Lighting Preset”. Choose your favorite, move the lights into the positions that you prefer, and you’re all set.

For a more custom solution, you can select the type of light (direction, point, spot, or hemi), its color, and other settings relevant to each of the light types.

Ground Shadows

Ground shadows are often the finishing touch on an otherwise impressive model presentation. By enabling ground shadows, you create the illusion of a ground plane beneath your model, thereby giving it an anchor in space and an extra dash of realism.

Baked Ambient Occlusion (AO) ground shadows work for static (non-animated) models. They’re great for giving the look of an object sitting on the ground or on a table surrounded by ambient light. Baked AO ground shadows can be used with Lit or Shadeless rendering.

• Intensity controls the darkness of the shadow. Higher numbers indicate a greater intensity and darker shadow.
• Border fade determines the gradient between the shadow’s border and the center of the bottom of the model. Lower numbers result in a larger fade area, while higher numbers limit the amount of space allowed for the shadow to fade. A setting of 1 can lead to sharp edges on your ground shadow.
• Height can be adjusted to ensure that the ground shadow is not cast above or below the base of your model. If you have set your model on the grid plane in Scene > General > Show Advanced Rotation, you may not need to adjust the height setting at all (or only a little bit).
• Shadow diffusion controls how sharp or diffuse your shadow is. Higher values provide more diffuse shadows and lower values result in denser, more defined shadows.

Shadow Catcher ground shadows work for both static and animated models. These shadows give the impression of being in a space with a directional light (e.g., the sun). The shadow catcher can only be used in Lit rendering mode when there are one or more shadow-enabled lights present.

• Intensity controls the darkness of the shadow. Higher numbers indicate a greater intensity and darker shadow.
• Border fade determines how constrained the ground shadow’s fade will be. Lower numbers result in a larger fade area, while higher numbers limit the amount of space allowed for the shadow to fade. A setting of 1 may result in the shadow fading away relatively close to your model.
• Height can be adjusted to ensure that the ground shadow is not cast above or below the base of your model. If you have set your model on the grid plane in Scene > General > Show Advanced Rotation, you may not need to adjust the height setting at all (or only a little bit).
• Size controls the amount of space that the shadow is permitted to inhabit. Smaller numbers indicate a smaller area for the shadow. If the size is set too small, your ground shadow may be clipped.

And that’s it! Now it’s time to try out some of your lighting knowledge on your own uploads.