Slopefoil Normal Maps
Height PNG to surface normals
$3.99 · Designed for iPad. Not verified for macOS.
Give your height pixels a surface. Inspect actual normals under light, check repeated edges, then share both Y conventions and a source-backed project. One purchase.
Slopefoil is an offline height-to-normal workshop for iPhone and iPad. Make actual texture files from your owned PNG and keep the source and controls together.
SHAPE THE SURFACE
Import a static 8-bit height PNG from Files, or restore a Slopefoil project JSON. Choose stored Luma, Red, Green, Blue or Alpha as height. Adjust slope strength, box smoothing, height inversion and Wrap or Clamp edges. Undo the last 20 control changes. Save up to eight treatments per project.
SEE WHAT YOU MAKE
Switch between processed Height, actual +Y Normal and an illustrative lit plane. Adjust light azimuth, elevation and softness. These preview controls do not change exported normals. Inspect a 2x2 repeat and actual opposite-edge height differences. Wrap changes sampling; it does not make a non-seamless image seamless.
TAKE REAL FILES
Export opaque RGBA8 Normal-PlusY.png and Normal-MinusY.png, processed grayscale Height.png, illustrative Lit.png, byte-identical Source.png, a surface-proof PDF, Measurements.csv, Readme.txt and a restorable Project.json containing the original source and controls. Share individual files or the complete nine-file ZIP. Preview the actual PDF. Choose the Y convention and non-color/linear import setting required by your destination editor and inspect its result. Destination-engine compatibility is not certified.
KEEP REUSABLE WORK
Save up to 20 source-backed local projects. Rename, duplicate, reopen and delete them. Production begins empty; an optional original wave study is generated on device. Save your project before leaving. iPad provides a broad surface viewport beside controls; large accessibility text uses a scrollable arrangement.
INPUT AND MATH
Static non-interlaced 8-bit gray, RGB, gray-alpha or RGBA PNG only, 8-1024 pixels per side and 12 MB. Palette, 16-bit, animated PNG and tRNS transparency are unsupported. Stored channel bytes are read without gamma or ICC conversion. Luma uses weighted code values; RGB modes ignore alpha, while Alpha reads it as height. Source bytes remain unchanged.
Normals use central per-texel height derivatives, scaled by strength 0-64. Box smoothing has radius 0-3 pixels. PlusY encodes the normalized vector (-dH/dx,+dH/dy,1), with source y increasing downward; MinusY negates its Y component. RGB=(vector+1)/2, quantized to 8-bit, with opaque alpha. Generated PNGs omit source profiles and metadata. Heights and light are illustrative, not measured geometry. No AI inference, sculpting, mesh baking, AO/roughness generation or physical PBR measurement.
200 MB retained source-library limit; project JSON imports up to 20 MB. Keep your originals separately and use images you have rights to process and share.
One upfront purchase. No subscription, IAP, account, ads, analytics, tracking, cloud sync or developer upload. Files stay on the device unless you share them.
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The developer, Gobling Company, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Gobling Company
- Size
- 6.3 MB
- Category
- Graphics & Design
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Age Rating
4+
- 4+
- Copyright
- © 2026 Gobling Company
