IBL Filter

Generate diffuse irradiance maps and specular pre-filtered environment maps from HDR images for PBR image-based lighting. Configurable roughness levels for real-time and offline renderers.

Drop your HDRI file here

or browse — HDR, EXR, TIFF up to 256MB

GGX Importance Sampling
GGX Importance Sampling
Lambertian Diffuse
Both (Diffuse + Specular)
OpenEXR (.exr)
OpenEXR (.exr)
Radiance HDR (.hdr)
PNG 16-bit
64
32
64
128
256
512
256
512
1024
2048
4096

Related Tools

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Light Probe
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Lighting Setup
Create studio lighting rigs with HDR environment maps.
FAQ

Frequently Asked Questions

Diffuse IBL uses a Lambertian convolution of the HDRI to provide ambient diffuse lighting. It's a single low-resolution map (typically 32x16 or 64x32) that represents omnidirectional indirect light. Specular IBL pre-filters the HDRI at multiple roughness levels using GGX importance sampling, creating a mipmap chain where each mip level corresponds to a roughness value. Together they enable full PBR environment lighting.
The mipmap chain stores pre-convolved versions of the environment map at increasing roughness levels. When rendering, the shader samples the appropriate mip level based on the material's roughness value. This avoids expensive real-time convolution and provides accurate microfacet BRDF reflections. Without a pre-filtered chain, real-time IBL specular would be impossibly slow.
256: Quick preview, some noise. 512: Good balance for most use cases (recommended). 1024: Production quality with minimal noise. 2048-4096: Near-perfect convergence for film/VFX. Higher sample counts produce smoother results but take significantly longer. For real-time game assets, 512 samples is usually sufficient.