# Anybody know how the Blend Space interpolation algorithm works?

**URL:** <https://forums.unrealengine.com/t/anybody-know-how-the-blend-space-interpolation-algorithm-works/102044>\
**Category:** C++\
**Tags:** unreal-engine, Engine-Source-Code, GitHub, Engine-Source-GitHub\
**Created:** [November 1, 2017, 10:41am UTC](https://forums.unrealengine.com/t/anybody-know-how-the-blend-space-interpolation-algorithm-works/102044 "2017-11-01T10:41:38Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kamrann](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@kamrann](https://forums.unrealengine.com/u/kamrann)\
**Post date:** [November 1, 2017, 10:41am UTC](https://forums.unrealengine.com/t/anybody-know-how-the-blend-space-interpolation-algorithm-works/102044/1 "2017-11-01T10:41:38Z")

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I’m looking into this code to see if I can reuse the core of it for non-animation related value blending. Really struggling to work out what it’s doing though. I can see there’s a Delaunay triangulation going on in the preprocessing, but I don’t follow how it’s calculating the weights. I’m also kind of surprised to see that it apparently doesn’t limit itself to the closest samples - I would have thought the reason to restrict samples to a regular grid was to simplify the blending process in this way.

My experimentation has shown that the following case

[https://forums.unrealengine.com/filedata/fetch?filedataid=121581&type=thumb](https://forums.unrealengine.com/filedata/fetch?filedataid=121581&type=thumb)

not only gives a weight to the bottom right sample, it actually has a larger one than the bottom center sample (albeit both are very low). Maybe an effect of the sparse samples in my test, but seems a little strange.

Anyone have any insight?

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**Author:** ![KeyC0de](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/keyc0de/32/1099072_2.png) [@KeyC0de](https://forums.unrealengine.com/u/KeyC0de)\
**Post date:** [August 29, 2025, 9:36pm UTC](https://forums.unrealengine.com/t/anybody-know-how-the-blend-space-interpolation-algorithm-works/102044/2 "2025-08-29T21:36:26Z")

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Hello, could you figure this one out?