Lens distorsion map

[serdar_turanl]

I’m looking for this lens map. This feature was announced, but there are two maps on the site. I need the map in the image I like the most.

[Alexander.Atanasov]

Hi serdar_turani,

May I ask where did you get this image from? One of the available distortion maps in our docs site (Camera Tab) is a fisheye camera. If you crop the distortion map to not include the black corners you could get a similar results to the one you want:

Both images(left uses the original lens_distortion_fisheye.exr and the right uses lens_distortion_fisheye_cropped.exr) have a large FoV(120) and use Outside for the Texture fit of the distortion map. Please test the attached cropped fisheye distortion map to see how it looks on your end.

Best regards,
Alexander
lens_distortion_fisheye_cropped.zip (851 KB)

[serdar_turanl]

@Alexander.Atanasov

Hi serdar_turani,

May I ask where did you get this image from? One of the available distortion maps in our docs site (Camera Tab) is a fisheye camera. If you crop the distortion map to not include the black corners you could get a similar results to the one you want:

Both images(left uses the original lens_distortion_fisheye.exr and the right uses lens_distortion_fisheye_cropped.exr) have a large FoV(120) and use Outside for the Texture fit of the distortion map. Please test the attached cropped fisheye distortion map to see how it looks on your end.

Best regards,
Alexander

Thank you very much. You made me very happy.
Is there another site where I can find more of these, or any place where they are shared collectively?

[piotrus3333]

it’s just distorted exr - every software capable of saving exr and having some sort of lens distortion is enough.

[s.balabanov]

Hi serdar_turanl ,

To create a custom fisheye lens distortion map for Chaos Vantage, you are essentially authoring an ST Map (sometimes called a UV Map). Think of this map as a “lookup table” that tells Vantage: “For this pixel on the screen, look at these specific coordinates in the 3D scene.”
Because you are dealing with pixel-perfect coordinates, you must work in 32-bit Floating Point mode. Using 8-bit or 16-bit will result in “stepping” or “staircase” artifacts in your final render because there aren’t enough colors to describe smooth sub-pixel movements. Here are the basic steps that you can use to recreate a distortion texture in popular image editing software:

1. Project Setup (Photoshop or Krita)

First, create a canvas that matches your intended render aspect ratio (e.g., 1920x1080 or a square 2048x2048 ).

• In Photoshop: Go to Image > Mode > 32 Bits/Channel.
• In Krita: When creating a new file, under Color Model, select RGB/Alpha and set Depth to 32-bit float.

2. Create the initial non-distorted “Identity” Map (The Linear Base)

Before adding distortion, you need a non-distorted map where every pixel points to itself. This looks like a red and green gradient.

1. The Red Channel (Horizontal/X):
   • Open your Channels panel. Select only the Red channel (hide Green and Blue).
   • Use the Gradient Tool. Set it to a linear “Black to White” gradient.
   • Click and drag from the far left edge to the far right edge.
   • Result: Pure black on the left, pure red on the right.
2. The Green Channel (Vertical/Y):
   • Select only the Green channel in the Channels panel.
   • Vantage (and most 3D software) expects the vertical coordinate to start at the bottom.
   • Click and drag your gradient from the bottom edge to the top edge.
   • Result: Pure black at the bottom, pure green at the top.
3. The Blue Channel:
   • Select the Blue channel and fill it with pure Black (0). It is not used for coordinates.

3. Creatung the Fisheye Distortion

Now that you have a “linear, non-distorted” map, you need to “bend” it. The distortion you apply to this map will be the distortion Vantage applies to your render.

• In Photoshop:
  1. Ensure all channels (RGB) are visible/selected.
  2. Go to Filter > Distort > Spherize
  3. Set the Amount to a positive value (e.g., +50% to +100%) to create a “bulge” or barrel distortion typical of fisheye lenses.
  4. Alternative: Use Edit > Transform > Warp for more artistic, non-uniform control.
• In Krita:
  1. Go to Filter > Distort > Lens Distortion or Fisheye.
  2. Adjust the sliders until the linear grid of the red/green gradient appears “pushed out” from the center.

4. Export map

Vantage requires a high-dynamic-range format to read the 32-bit coordinate data correctly.

• Save As/Export: Choose OpenEXR (.exr).
• Settings: Ensure it remains 32-bit (Full Float). Do not apply any “Color Space” conversions or “Gamma” corrections upon export; the data must remain “Linear” or “Raw.”

5. Load into Vantage

1. Open Chaos Vantage and go to the Camera tab.
2. Find the Lens Distortion section and enable it.
3. Click the Load folder icon and select your exported .exr map.
4. Set Texture Fit to Inside or Stretch depending on how you authored your map relative to your render resolution.

Additional considerations:

• If you are trying to match a specific real-world lens, you may need a “Lens Grid” (checkerboard) photo from that lens to overlay as a guide while you warp/distort your map.
• If the “Spherize” filter makes the image look “pinched” (pincushion) instead of “bulged” (barrel), you need to use a negative value in the filter settings.