OTOY Forums

Hey there,

I am trying to have a camera parented to a police car as it zooms past several buildings, motion blurring the fast motion scenery around the police car. What I am actually getting is motion blur on everything, including the police car which is stationary in the camera. I am including two projects, the first one shows that what I am going for is possible, and the second one (a simplified version of my scene using cloned cubes instead of buildings) contains this motion blur problem. I don't understand why parenting a camera to a simple primative works, but when I parent a camera to a more sophisticated object the motion blur behaves unexpectedly. I have tried all combinations of object tag placement on parts I want to have motion blur and those I want not to have it.

Any help is greatly appreciated,

Ben

Hi prisonbread,
I downloaded your scene, and it seems to render the same as your sphere example.
This is a still frame sample.

What version of octane are you on?

niestudio wrote:Hi prisonbread,
I downloaded your scene, and it seems to render the same as your sphere example.
This is a still frame sample.

What version of octane are you on?

with 3.05.3. I can't see any problems me too. What/where do you get?

That is really strange that it is working for you guys, or I guess strange that it's not working for me. I am running R18.048 of Cinema and Octane 3.06. I am encouraged to know that it works for you guys. Let me mess with it some more and see what happens.

As always thanks for your time!

-Ben

This happens to me all the time! You need to put an Octane object tag on your police car that your camera is parented to, and set the motion blur mode to Transform/Vertex. Just put the tag on the root of the police car. Also, you may find that it still looks messed up in the live viewer, but that often goes away when you render to picture viewer. Hope that helps! I'm gonna do a tutorial on this soon because it's an issue that not many people know how to solve.

daabomb101 wrote:This happens to me all the time! You need to put an Octane object tag on your police car that your camera is parented to, and set the motion blur mode to Transform/Vertex. Just put the tag on the root of the police car. Also, you may find that it still looks messed up in the live viewer, but that often goes away when you render to picture viewer. Hope that helps! I'm gonna do a tutorial on this soon because it's an issue that not many people know how to solve.

I'm not sure that's similar case you mention. But you don't need to use "transform/vertex", just "transform" enough if you don't have animated vertexes. Also you may need to render to PV if you have extreme PSR because LV will use one frame caching. But it will display correct when you restart render on LV and PV will display correctly if you have enough "time steps".

aoktar wrote: I'm not sure that's similar case you mention. But you don't need to use "transform/vertex", just "transform" enough if you don't have animated vertexes. Also you may need to render to PV if you have extreme PSR because LV will use one frame caching. But it will display correct when you restart render on LV and PV will display correctly if you have enough "time steps".

Thanks for the tip Ahmet! Yeah, that makes sense that only transform is enough the majority of the time, though in many cases I'll have the camera parented to a character that is animating, so in those cases, I'm assuming the deformations are on the vertex level and transform / vertex would be needed to also get the motion blur from the character's internal movement?

I've also noticed, as you've said, that if I restart the render in the LV, I'll get a preview of the correct motion blur, but if I move to another frame, the character or child object will then smear back out. Is there a control for time steps that I'm not aware of? Thanks!

daabomb101 wrote: Thanks for the tip Ahmet! Yeah, that makes sense that only transform is enough the majority of the time, though in many cases I'll have the camera parented to a character that is animating, so in those cases, I'm assuming the deformations are on the vertex level and transform / vertex would be needed to also get the motion blur from the character's internal movement?
!

Yes you need that for a character animation. Btw I'm storing relative movement for vertices + PSR animations. And transfer to renderer.

I've also noticed, as you've said, that if I restart the render in the LV, I'll get a preview of the correct motion blur, but if I move to another frame, the character or child object will then smear back out. Is there a control for time steps that I'm not aware of? Thanks

I've prepared a picture with notes to explain what's happening in depth. Additional information: When you scrub in timeline you need to go over a few frames to allow the plugin for storing enough frames. It's working with a caching system. For example, when you jump to frame 10, it will need to know PSR/vertex positions for extra frames(8,9/etc.. depends to shutter time and direction of mblur). So you can force to save it by going a few frames back.

aoktar wrote:I've prepared a picture with notes to explain what's happening in depth. Additional information: When you scrub in timeline you need to go over a few frames to allow the plugin for storing enough frames. It's working with a caching system. For example, when you jump to frame 10, it will need to know PSR/vertex positions for extra frames(8,9/etc.. depends to shutter time and direction of mblur). So you can force to save it by going a few frames back.

Very cool. Thanks for the detailed breakdown! I'll make sure to reference it when I do my quick tip video on motion blur in a few weeks. Thanks!