Height From Image

Overview

The entry point for turning hand-drawn art into 3D: it estimates a height map (white = high) from an ordinary 2D image. Even a flat-color sprite can be inflated from its silhouette for a rounded sense of depth. Use the output for lighting—such as the height input of image_to_surface—or as a map for slope_blur.

Usage tips

• Choose the mode by source: flat-color art → Silhouette, which inflates from the outline; already shaded art → Luminance, which uses brightness directly as height.
• Set the Silhouette shape with profile: character or rounded object → Round; crystal or spike → Linear; brick or box → Round plus plateau around 0.5 for a flat top.
• The go-to pipeline is image_load → height_from_image → image_to_surface(Height input) → surface_light_preview. It adds light and shadow to hand-drawn art after the fact.
• The output is an Image, so it cannot connect directly to the Surface input of surface_light_preview; route it through image_to_surface.
• It is also useful as a map for slope_blur, letting patterns flow along the shape of the artwork itself.

Common pitfalls

• Internal relief such as a recessed window is missing: Silhouette mode estimates from outline information only (see "Limitations" below). Reuse painted shading with Luminance, or draw the height map by hand.
• The height is jagged: an anti-aliased input edge destabilizes the silhouette. Insert threshold(Alpha) upstream to create a clean binary silhouette.
• The shape bulges when it should be recessed: turn invert ON to carve inward.

Technical details

• Silhouette: applies a chamfer 3-4 distance transform to the alpha silhouette, creating a height field that rises with distance from the edge. Round uses a hemispherical cross-section; Linear is conical. plateau caps the center at maximum height.
• Luminance: reads pixel luminance directly as height, making it suitable for reusing already-painted shading.
• Alpha: reads opacity directly as height.
• Transparent pixels remain transparent in the output.

Examples

• Use image_load → height_from_image → image_to_surface(Height input) → surface_light_preview to light a flat-color sprite after the fact.
• Turn 反転 ON to create recessed ornament or engraving.

Limitations

Because the estimate uses only the silhouette outline, it cannot represent internal relief such as a recessed window in a house. Draw the height map by hand when internal steps are needed, or reuse painted shading with 明るさ mode.

Related nodes

• image_to_surface — incorporate the height map into a Surface for lighting
• quick_shade — beginner-friendly one-node inflation and lighting
• slope_blur — flow a pattern along height-map slopes
• distance_field — when you need the distance field itself