diff --git a/zenovis/xinxinoptix/DisneyBRDF.h b/zenovis/xinxinoptix/DisneyBRDF.h
index 107b78539e..eabde964d8 100644
--- a/zenovis/xinxinoptix/DisneyBRDF.h
+++ b/zenovis/xinxinoptix/DisneyBRDF.h
@@ -5,10 +5,12 @@
 
 namespace BRDFBasics{
 static __inline__ __device__
-float PowerHeuristic(float a, float b)
+float PowerHeuristic(float a, float b, float beta = 2.0f)
 {
-  //float t = a * a;
-  return b>10.0f*a?(a/(a + b + 1e-6)) : (a*a/(a*a + b*b + 1e-6));
+    float t  = pow(a,beta);
+    float t2 = pow(b, beta);
+    return t / (t2 + t + 1e-6);
+  
 }
 static __inline__ __device__  float fresnel(float cosT){
     float v = clamp(1-cosT,0.0f,1.0f);
diff --git a/zenovis/xinxinoptix/PTKernel.cu b/zenovis/xinxinoptix/PTKernel.cu
index d07135a268..8141e41c5b 100644
--- a/zenovis/xinxinoptix/PTKernel.cu
+++ b/zenovis/xinxinoptix/PTKernel.cu
@@ -348,8 +348,6 @@ extern "C" __global__ void __raygen__rg()
                 break;
             }
 
-            //if(prd.depth>prd.max_depth) {
-
             if(prd.depth > prd.max_depth){
                 float RRprob = max(max(prd.attenuation.x, prd.attenuation.y), prd.attenuation.z);
                 RRprob = min(RRprob, 0.99f);
@@ -478,7 +476,7 @@ extern "C" __global__ void __miss__radiance()
 
         );
 
-        float misWeight = BRDFBasics::PowerHeuristic(prd->samplePdf,envPdf);
+        float misWeight = BRDFBasics::PowerHeuristic(prd->samplePdf,envPdf, 1.0f);
 
         misWeight = misWeight>0.0f?misWeight:0.0f;
         misWeight = envPdf>0.0f?misWeight:1.0f;