Which 3D apps read .hdr environment maps?

Radiance HDR (.hdr, sometimes .pic) is the original high-dynamic-range image format developed by Greg Ward at LBL in 1985, and despite its age it remains the standard interchange container for environment maps in Blender, Cinema 4D, Houdini, Unreal Engine, and V-Ray. The format stores RGBE pixels (three 8-bit color channels plus a shared 8-bit exponent) which encode roughly 76 orders of magnitude of luminance range in a 32 bits-per-pixel structure - perfect for image-based lighting (IBL) where the brightness ratio between sun and shadow needs faithful representation.

Converting HEIC to HDR is a repackaging step, not a true HDR capture - but HEIC is a better starting point than an old 8-bit JPG. iPhone HEIC files store 10-bit HEVC-encoded data, and recent iPhones attach an HDR gain map, so decoded tonal gradients are smoother and hold slightly more usable headroom than 8-bit sources. Still, real HDR captured via bracketed exposures contains 20+ stops; the converted .hdr inherits only whatever range survived the camera's tone mapping. Wrapping it in the RGBE container makes it loadable as an environment map by 3D software that refuses HEIC or any LDR input outright.

VFX artists and Unreal Engine lighting TDs convert HEIC to HDR most often when a location scout or client shot reference panoramas on an iPhone and the deck needs to drive a quick lookdev pass - throwing that HEIC sky at a Blender world shader via this conversion is faster than re-bracketing the scene. Real production lighting still demands true 32-bit float HDR from bracketed captures, but the converted .hdr is sufficient for blocking, animation reviews, and quick technical tests. For the reverse direction see HDR to HEIC.

Reasons to convert HEIC to HDR usually come down to compatibility, file-size, or specific feature requirements. Common situations:

• An app or platform only accepts HDR uploads.
• You need a feature unique to HDR (e.g. transparency, vector scaling, animation, multi-page pages, etc.) that HEIC doesn't provide.
• You're optimising file size — modern formats often produce smaller files than the older format you started with.
• You need a single archival format across a project so files behave consistently in the same viewer.

1. Open the HEIC → HDR tool on heic.now.
2. Drag your HEIC file onto the drop zone, or click Select files. You can drop a whole folder of files at once.
3. The output is fixed to HDR. If the format supports extra options (page size, transparency background, quality, EXIF stripping), tweak them in the right-hand panel.
4. Click Convert. The job runs on our server and finishes in a few seconds for typical photos.
5. Download the result. Files stay in storage for 24 hours and are then permanently deleted.

The entire flow is free for the first 10 jobs per day with no signup required. A free account doubles that quota; a premium plan removes the limit entirely.

• Use equirectangular (2:1 aspect, latlong) sources if the target is a Blender or Unreal environment map - iPhone panorama HEICs work, but the HDR container won't fix a flat single-frame photo.
• For Blender, drop the .hdr into World > Surface > Environment Texture - the engine reads RGBE natively and applies it as IBL with no further conversion.
• Don't expect highlight recovery - converting HEIC to HDR can't reconstruct a clipped sun or window that the iPhone's tone mapping already discarded. Source from RAW or bracketed exposures for true HDR.
• If you need 32-bit float precision rather than RGBE, convert to OpenEXR (.exr) instead - it's the production standard for film and supports per-channel float values plus arbitrary layers.
• Sites like Poly Haven, HDRMAPS, and HDRI Hub provide free real-HDR environment maps if your HEIC-to-HDR result lacks the dynamic range your lighting setup needs.