Corona Tree rendering Slow

[dfcorona]

Hi, Great job on corona! Been testing it out against Vray next and Redshift.  It is really fast CPU renderer for interiors.  Exteriors I'm having some issues, seems rendering vegetation and such is really slow.  I wanted to know what I might be doing wrong.  I render  same exterior tree with Vray and it renders in less than half the time.  I am just testing one tree to see the difference, and the difference is rather large.  I even put basic material one each to test and Corona still seems a lot slower.  I'm sure it's something I might be doing.  I am using an HDRI for lighting, Plane for floor and one tree.  Any suggestions?

[Bormax]

Hi
Strange. I was always happy how fast Corona can handle huge amounts of all kind of green stuff. I believe something wrong with leaves or with something else. Do you use Path Tracing/Path Tracing setup? Path Tracing/UHD Cache cleans picture faster

[maru]

Actually using path tracing + path tracing in exterior shots may be the better solution.

As to the main problem - please check if your tree does not use a material with refraction enabled for the leaves. This sometimes happens after converting scenes from Vray.
Other than that, a screenshot of the VFB with "stats" tab open, and generally showing us the rendered scene would greatly help.

[Bormax]

Actually using path tracing + path tracing in exterior shots may be the better solution.

Could you tell me, please, why I always see in tutorials, that PT/PT is better for exterior scenes? Yes, it has faster feedback if we are talking about IR or drafts, but to render finals I always use PT/UHD, because whatever scene I've tried to render PT/UHD was always faster in cleaning than the PT/PT setup

[Bormax]

One more thing came to my mind - if you have adaptivity enabled, it could slow down cleaning picture with objects such as tree(s), grass, etc. Because there are lot of noisy points between leaves, grass blades, etc. which make difficult to make picture equally noisy all over the picture's area (not really good explanation, you should read more about adaptivity). But in fact you'll not see this noise because of amount of small details in tree's crown or grass field. At least in my exterior scenes I always disable adaptivity to speed up rendering, but I always keep it enable in interior scenes.

[Nejc Kilar]

Actually using path tracing + path tracing in exterior shots may be the better solution.

Could you tell me, please, why I always see in tutorials, that PT/PT is better for exterior scenes? Yes, it has faster feedback if we are talking about IR or drafts, but to render finals I always use PT/UHD, because whatever scene I've tried to render PT/UHD was always faster in cleaning than the PT/PT setup

Funny enough that is my impression as well. PT PT works for exteriors but from my impression (<- important word) it is mostly not as fast as UHD. Even with grass.

Whats the science here Maru? :)

[maru]

There is no science really, but:
-what you see in exteriors is mostly direct light
-uhd helps only with GI
-calculating the uhd cache is just one extra step, which may not be necessary for an exterior render, and it may slow down rendering overall, especially when rendering an animation

If the rendering works fine for you, and it renders faster with uhd, then it is fine to use it of course.

[dfcorona]

Thank you all for the responses and suggestions, I will try them and see how it works out.  Sorry I haven't replied earlier, for some reason I wasn't being notified of responses to this thread, even though I checked to be. It also doesn't show up in my "show new replies to your posts." link.  Something must have gone haywire.

I do have adaptivity on and using PT/UHD, I am also using a "noise level limit" this way I have even noise through animations.