Image Sampler UV

Extract color data from specific UV points on an image, with domain mapping, tiling, channel selection, and optional bilinear interpolation.

---

Creation method

Two Options for Creating an Image Sampler UV Node

1. Using Search List

   • Double left-click in the workspace to open the search list.
   • Type keywords: image, sampler, uv, color, analysis.

2. Select from Menu

   • Navigate to Tools > Image > Image Sampler UV.

---

Inputs

• Image (image) — Type: Image
  Accepts the source image to sample.

• Points (points) — Type: Point[]
  An array of UV points (x, y) in domain space (see Config below). Each point corresponds to one sampled output.

---

Config (optional)

• Tiling (T / tiling) — clamp | tile | flip (default: clamp)
  How samples behave outside the image bounds after domain mapping:

  • clamp: pins to the nearest edge
  • tile: repeats the image
  • flip: mirrors every other tile

• Channel (C / channel) — rgba | red | green | blue | alpha (default: rgba)
  Which channel(s) to read before converting to outputs.

• X Domain (X / xDomain) — [x0, x1] (default: [0, 1])
  Maps the U coordinate of your points from this domain into the image width.

• Y Domain (Y / yDomain) — [y0, y1] (default: [0, 1])
  Maps the V coordinate of your points from this domain into the image height.

• Interpolate (I / interpolate) — Boolean (default: false)
  Enables bilinear interpolation for smoother sampling between pixels.

Tip: With the default domains [0,1] × [0,1], UV (0,0) samples the image’s bottom-left and (1,1) the top-right (depending on your image origin; flip Y domain to match your convention).

---

Outputs

• Color (colorHex) — Type: Color
  Hex color #RRGGBBAA at each input point (alpha included).

• Hue (hue) — Type: Number
  Hue in 0..1. Multiply by 360 for degrees.

• Saturation (saturation) — Type: Number
  Saturation in 0..1.

• Brightness (brightness) — Type: Number
  Brightness/Value in 0..1.

---

Steps

1. Create an Image Sampler UV node.
2. Connect an image to Image.
3. Provide an array of UV Points (e.g., a grid, curve points, or any list of vectors).
4. (Optional) Adjust Config: set tiling, channel, domains, and interpolation.
5. Read Outputs: fetch Color, Hue, Saturation, and Brightness arrays—each aligned with the input points order.

---

Practical examples

• Sample along a curve: Convert curve parameters to UV points (e.g., t in [0,1] → (t, 0.5)), enable * Interpolate* for smooth gradients, and read Hue to drive geometry colors.
• Texture-driven scattering: Generate random UV points in [0,1]², set Channel to alpha to use image transparency as a density mask.
• Remap domains: If your UVs are in pixel space (e.g., x ∈ [0, W], y ∈ [0, H]), set X Domain to [0, W] and Y Domain to [0, H] for direct mapping.
• Edge handling: Use Tiling = tile for seamless textures; use clamp to avoid wrap artifacts on borders; use flip to reduce seams when mirroring.

---

Notes & best practices

• Ordering preserved: Output arrays align 1:1 with the input Points order.
• Color pipeline: Channel selection is applied before conversion to HS(B)V and hex.
• Alpha awareness: colorHex includes AA; use Channel = alpha if you only need the alpha mask numerically.
• Performance: Bilinear Interpolate improves quality at a small cost; disable it for large point sets when speed matters.
• Y-up vs Y-down: If your image origin is top-left, set Y Domain to [1, 0] (flip) to align with bottom-left UV conventions.

---

See Also

• Image Sampler (grid scanning)
• Image Dimensions
• Image GrayScale
• Image Edge Detection
• Image Preview