I want to use materials to achieve similar pie chart style, through parameters to control the number of angles, how should I achieve?
If I understand you correctly, you just want to use a single material, which you apply to a image widget or so?
Well, I don’t think thats possible with just materials.
The furthest a material can go to achieve a similar style would be in this forum post: link
I’m not sure how familiar you are with unreal’s slate api and c++, but if you want to do it in c++ with slate, it’s quite some work, but not impossible for sure. A combination of FSlateDrawElement::MakeLines() and/or MakeCustomVerts(). And every point which is lower as the Y position of the pie center gets drawn with an offset (thickness). To achieve the perspective you can ‘scale’ the Y position of the points towards the pie center the farther the X position is distanced from that center point.
But the easiest thing to do, would be a hacky way with procedural mesh generation.
Where you just create 3d meshes and capture the generated mesh with a render capture component, and that RenderTarget texture can be set as an resource for any widget.