how to use DrawMaterialToRenderTarget

when i use DrawMaterialToRenderTarget in EventTick to draw some random point,
I thought there would be more and more point in the RenderTarget2D, but only the last one left
and i donot use ClearRenderTarget2d,

Is the function “DrawMaterialToRenderTarget” is not what I think???

It depends on material type.
I think in your case draw material must be additive.