Hello @pali_rao ,
Would you mind also sharing the scene with me so I can have a look? Thank you.
Hi Aleksandar,
I tested the scene and I’ve created a new one as well, there is definitely something wrong with the motion blur sample system.
Increasing the number from 2 to a larger number create progressively wrong results. It looks like the effect become increasingly more transparent and in same case became almost invisible.
I can reproduce this on both Vray6 and 5 and C4D R25/26, works like that in every scene, here is a simple setup:
A couple test render with relative velocity channel.
Motion blur sample = 2:
Motion blur sample = 16:
cube mb.c4d (178 KB)
Thanks Aleksandar - I have emailed you the scene file. Im using VRay 6 on C4D 2023, but was getting the same results with C4D R26 and VRay 5.
Thanks @sirio76 for investigating!
Hey, Sirio, Pali,
Thank you for your excellent, fantastic support. I am almost 98.0% sure this is the correct behavior when using 16+ geometry samples. This is how it has worked since V-Ray Next.
Cheers,
Hi Boyan, this can not be right, for example in the car scene the motion blur became almost invisible with more samples. Since more samples may be needed for spinning parts like the wheels the mb is not usable. I will check also with an older scene with a propeller that worked for sure to see if something has changed.
I agree totally - I can get mo blur to work, but it does not seem possible to get more samples, as when you add a VRayObjectProperties tag, mo blur stops. Also this is whilst using a VRay Physical Camera with mo blur enabled.
@boyan @aleksandar.kasabov @shaio
This is the final result obtained with a movie camera for reference: https://www.youtube.com/shorts/hh16F\_Xfqhs
Here is a test on a single frame, this is what I get using a movie and a still camera with no motion blur samples.
Movie camera no samples:
Still camera no samples:
As you would expect the motion blur is fine but the propeller do not have a correct “circular” motion blur because you do not have enough samples.
So you increase the samples, I’ve used 16 here and this is what I get.
Movie camera 16 samples:
Still camera 16 samples:
Without the additional samples both movie and still camera produced very close results that feels correct beside the propeller issue, once you add more samples with the object properties tag the movie camera works great and you get a correct motion blur on the propeller, while on the still camera the result is much different and in my opinion simply wrong.
@pali_rao the good news here is that the movie camera worked perfectly so yo can use that and you will get perfect results.
Thanks @sirio76 That’s great to know! I agree, the still cam definitely does not look right. Next project, I’ll give movie camera a try. Now I know the issue, I’ll be able to workaround and hopefully the Chaos team will resolve..
Hey, Sirio, Pali,
Thank you both for the enormous effort and reports. This is a real example of how you people make the product great. I will keep you posted about it. I should go deep to the core.
Cheers,
Thanks Boyan!
Thanks Boyan! I love using VRay.
Hello @pali_rao ,
I checked your scene but I was not able to “remove” the motion blur by adding an Object Properties tag to an object in the scene. However, there seems to be a bug with the motion blur when changing the motion blur samples in the Object Properties tag (or the Overrides settings). I have reported the bug to our developers (bug ID: VC4D-1587) and I will keep you updated on the progress.
Thank you.
Thanks for investigating Aleksandar. Not sure why it was happening on my set up, but it very repeatable. Hopefully the fix for the bug will solve this. Will this be added to the dailies at some point?
Thank you
I can’t say anything at this point, but most probably we will add the fix to the stable builds once the bug is fixed. I will let you know once this happens.
Great, thanks buddy!