Shd Tab ‐ Shadows Settings - ApertureViewer/Aperture-Viewer GitHub Wiki

The Shadow Tab (labeled "Shd") in the Aperture Phototools Suite (APS) provides comprehensive controls for managing scene illumination, focusing on point lighting, shadow rendering, and Screen Space Ambient Occlusion (SSAO).

Lights & Shadows Settings

This section covers the primary settings for how lights are rendered and how shadows are cast in the scene.

Point Lighting & General Light Options (P_Light_Settings)

• Point Lighting (Restart) (LocalLightsDetail):
  • Function: A combobox that defines the maximum level of detail for local light sources (point lights, projectors).
    • Full (default): Renders all local lights with full features.
    • Reduced: May simplify some lighting calculations for performance.
    • Sun/Moon Only: Disables all local lights, only environmental light from the sun/moon is active.

[!NOTE] Changes to this setting typically require a viewer restart to take full effect. For most Aperture users, leaving this at "Full (default)" is recommended.

• Loc Lights (RenderLocalLightCount):
  • Function: A slider and spinner to control the maximum number of local light sources rendered simultaneously in the scene.
  • Range: 0 to 8192 (though practical limits and performance considerations apply).
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

  • [!IMPORTANT]

  A previous issue where this value was inadvertently clamped to 16 in some scenarios has been fixed in Aperture. Higher values allow for more complex lit scenes but can impact performance. Aperture's graphics presets manage this setting for balanced performance.

• Show Bounding Boxes for All Lights in Scene (Lights):
  • Function: When checked, displays wireframe boxes around all active light sources in the scene.
  • Purpose: Helps visualize the placement and effective range of lights, useful for debugging lighting setups or complex scene arrangements. The boxes are color-coded for easier identification (e.g., yellow for the main influence, light blue for the light object itself).
• Show Light Radius for Selected Light(s) (Show Light Radius for Selection):
  • Function: When checked, displays the effective radius of currently selected light sources.
  • Purpose: Allows you to visually gauge how far the light from a selected prim light reaches, aiding in precise lighting adjustments.

[!NOTE] The visual representation of the light radius is an approximation and may not perfectly match the perceived falloff.

Shadow Types (P_CB_Shadow)

• Shadow Types (ShadowDetail):
  • Function: A combobox to select which light sources cast shadows.
    • None: No shadows are rendered.
    • Sun/Moon: Only the primary environmental light (Sun or Moon) casts shadows.
    • Sun/Moon + Projectors: Both the Sun/Moon and local projector lights (spotlights with projected textures) cast shadows.

[!TIP] Standard point lights (without projection features) create illumination but do not cast shadows, regardless of this setting. Projected light textures (gobos) will remain visible even if shadows are set to "None" for the projector itself.

Shadow Settings (P_Shadow_Settings)

This panel provides detailed control over the quality and appearance of shadows cast by the Sun/Moon.

• Shd. Res (Shadow Resolution) (RenderShadowResolutionScale):
  • Function: Adjusts the resolution of the shadow map texture. Higher values produce sharper, more detailed shadows but consume more video memory and processing power.
  • Range: 0.5 to 4.0 (relative scale).
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

[!NOTE] In older viewer versions, taking very high-resolution snapshots with high shadow resolution could lead to crashes. This is believed to be largely resolved. For improving shadow quality, consider adjusting "Shd. Clarity" first.

• Shd. Clarity (Shadow Clarity) (SB_Shd_Clarity / S_Shd_Clarity):
  • Function: This Aperture-specific named control (linking to an underlying debug setting) significantly impacts the perceived sharpness and definition of shadows by adjusting how the shadow map is sampled, particularly in relation to shadow splits/cascades.
  • Range: 0.0 to 10.0 (custom range).
  • Default Reset Button (D): Resets to 0.150.

[!IMPORTANT] This is a key setting for achieving crisp, well-defined shadows and mitigating the "janky" or blurry appearance often seen with default shadow settings, especially at the edges of shadow cascades. It's often more effective and less performance-intensive than simply increasing Shadow Resolution. The optimal value can depend on camera angle and distance. Future Aperture versions aim to make the shadow system more intelligent, reducing the need for manual tweaking of such settings.

• Shd. Blur (Shadow Blur Size) (RenderShadowBlurSize):
  • Function: Controls the amount of blur applied to shadow edges. Requires SSAO to be enabled to see its full effect on softening.
  • Range: 0.0 (no blur) to 4.0.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Shd. Soften (Shadow Soften) (SB_Shd_Soften / S_Shd_Soften):
  • Function: Specifically adjusts the softness of the main shadow map edges, working in conjunction with "Shd. Blur".
  • Range: 0.001 to 5.0.
  • Default Reset Button (D): Resets to 0.800.
• Blur Dist. (Blur Distance Factor) (RenderShadowBlurDistFactor):
  • Function: Controls the distance from the camera at which shadow blur effects become more pronounced. A lower value extends the blur further into the distance; a higher value keeps sharper shadows closer to the camera.
  • Range: 0.0 to 1.0.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Spot Offset (Spot Shadow Offset) (RenderSpotShadowOffset):
  • Function: Adjusts the offset for shadows cast by projector/spotlights to help prevent self-shadowing artifacts.
  • Range: 0.0 to 0.04.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Shd. Bias (Shadow Bias) (RenderShadowBias):
  • Function: Modifies how closely shadows conform to the surfaces of objects. Incorrect bias can lead to shadows appearing detached ("Peter Panning") or causing shadow acne (shadows incorrectly appearing on the lit side of surfaces).
  • Range: -0.02 to 0.01.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset (Aperture uses a different default than some viewers).

[!IMPORTANT] Proper shadow bias is crucial for realistic shadow rendering. The optimal value can vary depending on scene scale and object geometry. This setting is also height-relevant; a bias value that works well for objects on the ground might need adjustment for objects higher up or for detailed avatar attachments.

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Ambient Occlusion Settings

Screen Space Ambient Occlusion (SSAO) adds contact shadows and a sense of depth where surfaces meet or are close to each other.

Enable SSAO (P_CB_Ambient_Occlusion)

• Enable Screen Space Ambient Occlusion (RenderDeferredSSAO):
  • Function: Checkbox to toggle SSAO on or off.

[!NOTE] SSAO can have a noticeable performance impact, especially with higher sample counts. The controls below are disabled if SSAO is off.

SSAO Parameters (P_Amb_Occ_Settings)

These settings fine-tune the SSAO effect when enabled.

• Samples (APRenderSSAOSampleCount):
  • Function: An exclusive Aperture Viewer control that directly sets the number of samples used for SSAO calculation. Higher sample counts produce smoother, more detailed, and less noisy AO, especially noticeable up close, but significantly increase performance cost.
  • Range: 0 to 1024.
  • Default Reset Button (D): Resets to 8.

[!IMPORTANT] For high-quality close-up AO (e.g., in portraiture), increasing samples (e.g., to 18 or higher in "Candy" presets) and reducing "Scale" (e.g., to 1.0) is recommended. The Aperture Viewer aims for more intelligent AO in the future that adapts better to camera distance and scene complexity.

• Scale (RenderSSAOScale):
  • Function: Controls the radius or spread of the AO effect. Lower values produce tighter, more localized AO; higher values create broader, softer AO.
  • Range: 0 to 500.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Max Scale (RenderSSAOMaxScale):
  • Function: Sets an upper limit on the SSAO scale effect, preventing it from becoming overly dominant at extreme distances.
  • Range: 0 to 500.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Factor (RenderSSAOFactor):
  • Function: A multiplier for the overall intensity of the SSAO effect.
  • Range: 0.0 to 5.0.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.

[!CAUTION] High "Factor" values can sometimes cause AO to "bleed" unnaturally from objects onto adjacent surfaces (e.g., from a box onto its own shadow). A value around 1.0 is often more realistic.

• Irrad. Max (Irradiance Max) (RenderSSAOIrradianceMax):
  • Function: Clamps the maximum influence of scene irradiance on the AO calculation.
  • Range: 0.0 to 5.0.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Irrad. Scale (Irradiance Scale) (RenderSSAOIrradianceScale):
  • Function: Scales the influence of scene irradiance on the AO.
  • Range: 0.0 to 5.0.
  • Default Reset Button (D): Resets to the value defined by the current Aperture Graphics Preset.
• Effect (SB_Effect / S_Effect):
  • Function: A general intensity control for the SSAO. Negative values can invert the effect (though this is usually not desired). 0 effectively disables the visible AO effect while 1 is full strength based on other parameters.
  • Range: -1.0 to 1.0.
  • Default Reset Button (D): Resets to 1.0.
• Saturation (SB_Saturation / S_Saturation):
  • Function: An Aperture-added control that allows color from surrounding surfaces to "bleed" into the AO shadows. 0 results in monochrome (grayscale) AO, while higher values introduce color.
  • Range: -1.0 (desaturated) to 1.0 (fully saturated color bleed).
  • Default Reset Button (D): Resets to 0.0.

[!TIP] Subtle use of AO Saturation can add realism by simulating how light reflects color onto nearby surfaces.

• AO Soften (SB_AO_Soften / S_AO_Soften):
  • Function: Specifically adjusts the softness of the SSAO effect itself, working in conjunction with "Shd. Blur" and "Shd. Soften" if shadows are also blurred.
  • Range: 0.001 to 3.0.
  • Default Reset Button (D): Resets to 0.500.

[!NOTE] A known issue exists where SSAO, particularly in conjunction with Screen Space Reflections (SSR), can cause visual artifacts (grid-like patterns or "acne") on water surfaces. This is an underlying viewer issue that is being investigated for future fixes.