# Material Blending makes unexpected Virtual texture lookup and stack counts

**URL:** <https://forums.unrealengine.com/t/material-blending-makes-unexpected-virtual-texture-lookup-and-stack-counts/2670383>\
**Category:** Rendering\
**Tags:** Virtual-Texturing, unreal-engine, question\
**Created:** [October 31, 2025, 6:04am UTC](https://forums.unrealengine.com/t/material-blending-makes-unexpected-virtual-texture-lookup-and-stack-counts/2670383 "2025-10-31T06:04:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![HadockAndChips](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@HadockAndChips](https://forums.unrealengine.com/u/HadockAndChips)\
**Post date:** [October 31, 2025, 6:04am UTC](https://forums.unrealengine.com/t/material-blending-makes-unexpected-virtual-texture-lookup-and-stack-counts/2670383/1 "2025-10-31T06:04:56Z")

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> **[Streaming Virtual Texturing in Unreal Engine | Unreal Engine 5.6 Documentation...](https://dev.epicgames.com/documentation/en-us/unreal-engine/streaming-virtual-texturing-in-unreal-engine)**
>
> An overview of the streaming virtual texturing method in Unreal Engine.

According to this page, virtual texture coast has two categories: lookups and stacks.

If two virtual texture uses the same uv, stack coast can be saved.

You can view lookups and stacks counts in the material stats.

When you are using Material Blending node with the value sampled from a virtual texture as the alpha value, the counts have unexpected results.

 ![vrtual texture interpolation](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/e/9/2e969c1617d5b13771329b1ee2dcae43fcab5ecd.png)

In above image, there are 3 virtual textures and all of the uses the same uv,

so there are 3 lookups and 1 stack, and the stat also shows the expected result.

 ![vrtual texture interpolation text](https://d3kjluh73b9h9o.cloudfront.net/original/4X/c/4/6/c469bec937b7c693cc9609d7c9e9a683ff1daecb.png)

I expected the same counts when material blending node is used instead.

 ![vrtual texture material blending](https://d3kjluh73b9h9o.cloudfront.net/original/4X/3/a/e/3ae7bb86caa4d39305b46be41d47f75cb736c0ce.png)

However, actual result is not what I expected.

 ![vrtual texture material blending text](https://d3kjluh73b9h9o.cloudfront.net/original/4X/d/d/1/dd192aac9afd564a7bca6cf7a7627c5cc8106673.png)

There are 5 lookups and 2 stacks. 2 more lookups and one more stack than expected.

If I use just a constant alpha value on the material attributes blending node,

 ![vrtual texture material blending constnat alpha](https://d3kjluh73b9h9o.cloudfront.net/original/4X/6/4/1/641630f48007a7b5b9746c8fbef21749afce2418.png)

it gives expected result: 2 lookups and 1 stack

 ![vrtual texture material blending constnat alpha text](https://d3kjluh73b9h9o.cloudfront.net/original/4X/6/8/d/68da12811d68128bce555aa67ea572c25f8545c6.png)

So I simplified both materials, only using one virtual texture to get the alpha value.

Material with linear interpolation node gives expected counts. 1 lookup and 1 stack.

 ![blending with vt alpha with lerp](https://d3kjluh73b9h9o.cloudfront.net/original/4X/5/d/9/5d9899cd7483e674491d7bf06225aa7484d5ec2f.png)

Material with attributes blending node gives 3 lookups and 2 stacks

 ![blending with vt alpha with material blend](https://d3kjluh73b9h9o.cloudfront.net/original/4X/e/4/4/e443645783835ff4e853ad118e22c3aa169ebf46.png)

It seems using VT sampling as the alpha value for Material Attributes Blending node gives 2 extra lookups and 1 extra stack.

Does anyone know why this nodes gives these extra counts?