So, grabbed a model I have and playing with lighting, camera, etc. to figure out the Mantra render within Houdini (12.1). I'm working on the scene and using the Render View tab with the auto update active to try out different settings and everything looks fine - as expected. I should mention I'm fairly new to Houdini.

Then I setup a Mantra render Node to render a 25 frame sequence with the exact same settings as the Render View tab. However, I don't get the same results. See attachments. Anyone have any idea as to what is happening? Literally, these are the exact same settings except one was rendered through the Render View tab and the other through mPlay window. I'm on a Windows7 64-bit machine with a AMD FirePro v7900 card. Feel free to ask other info if what I've said isn't enough.

Appreciate any help or insights you might have. Thanks!!

There nothing wrong with your shades, there's differences between the IPR and the mantra ROP. Post your scene file up

Rob

File is 15MB and won't let me post (5MB file size limit). I should also mention though that even in a default scene file with a cube the default ipr Render View is rendering as expected and the default ROP is doing the same thing as above.

Post a scene up using basic geometry ! As I have said viewing the IPR and Mantra ROP you will get differences. I use the IPR to get into the ball park in no way should it be used to decide on final render settings

rob

File attached. I noticed that if I change the Mantra ROP engine to Ray Trace I get the same results as the ipr. The only issue is, the ipr is on MicroPoly engine and it's getting clean renders. When I put the ROP on MicroPoly it gets well, crap renders. Just my observations as a newbie.

Thanks!!

If you are using the gradual refinement mode in IPR (“Preview” toggled on), then it uses the raytrace engine in IPR even if the ROP is set to Micropoly engine. If you toggle “Preview” off, then IPR always uses the engine defined in the ROP.

As eetu said. The ROP Output Driver has the Render Engine set to Micropolygon Rendering but the ipr render view when Preview is toggled on (generates geometry cache for quick re-lighting) only supports raytraced primary sampling (which supports shadow maps if you wish in lieu of raytraced shadows if lights are set as such). Even if the ROP has Micropolygon rendering set, ipr will force raytracing for primary samples for quick re-lighting of the scene.

As for the noise you see, this is caused by the micropolygon render engine having far too few Environment Light samples set on the Environment Light. If you crank the Environment Light samples to 32 or 64, the noise is greatly diminished in Micropolygon rendering mode.

Almost all settings are shared between all render engines to get similar results spare a few parameters of which sampling of Environment Light sampling is one.

Fantastic! Thank you jeff and eetu. That helps explain a lot. Especially about the Micro Poly render issue and Enviro light samples. The thought never occurred to me to check the light samples. D'uh. I think Houdini is psyching me out. I'm so “overwhelmed” with the software that my brain is checked at the door and I'm overlooking some of the most basic things.