Ithis is a default settings for rendering,but looks has any problom with marked place,why?Yhe version is H13,I had do nothing.but it very nice in H12

Can you upload the .hip file. Can't really see the problem yet. Thanks!

Some of the parameters and setting in the Houdini 13 changed ,for example :

Default renderer in the Houdini 12 is “Micropolygon Rendering” and default renderer for Houdini 13 is “Ray Tracing”.

Transparent Samples in Houdini 13 is 4 ,But in the H12 is 1 !

Defalut Gamma (Color Space) in the Houdini 13 is 2.2 ,But in the H12 is 1.

Also some different parameters added in the Houdini 13 Mantra node like :
“Allowable Paths” , “Color Limit” , “Min Reflection Ratio” in the Shading tab.

So you should set parameters manualy to achieve same result in the H13

This is hip file