The problems I'm having with Iray plugin IC8 is 1st, any video motion I plug into the various channels (Diffuse, Bump, Displacement) to create a water motion or anything of that nature on a regular plane, it's not being shown using Iray after I do the final rendering of the frames. Unlike IC7 where as I see the motions on the plane after applying the video motions to the channels in the final rendering. 2nd, I notice that the Iray plugin for IC8 Sun and Sky is not displaying the sun and sky lighting distinctively as it does in IC7. I get true soft or hard shadows after messing with the settings in iC7, but in iC8 the sun and sky just gives this soft look all around in spite of me messing with the settings. I've sent attachments to show my issue.

IC7 Iray - video motion file on the shader channels



IC8 Iray - video motion file on the shader channels

S
SShader channels

Displacement maps cause issue with Iray in IC8. There is a ticket already assigned for that: https://www.reallusion.com/FeedBackTracker/Issue/Cloth-items-becomes-static-with-Iray-render-if-tessellated-or-have-a-displacement-map
(you may add your comment there with this particular problem)

Sun and sky is no issue for me though (no other lights in the scene).

Okay thanks for the reply, but I tried it without the displacement map channel and I put the video motion in the bump channel ONLY and I'm still getting the same results.

Oh boy... hot mess with Iray in IC8 (I have not rendered for a while)...

Yes, it has real trouble with embedded videos. It does not render them leaving it static.
On top of that it takes whole lot longer!

MI scene for my basic project with a video was built in 20 seconds in iClone 7 (60 frames).
Same project in iClone 8 would take 16 minutes to extract MI scene (I did not wait till the end - just estimated based on current speed).

If I take a prop with video out, then iClone 7 build MI scene in 5 seconds, while in iClone 8 it takes 8.5. Still almost twice as slower.

Anyway, you may want to submit a ticket in FT about the issue. I've had enough with Iray

Lol. I feel you on having enough with the Iray feature in iC8 4u2ges! I do have a nice work around to get Iray to work in my favor using iC8 but what's stopping me is this video motion on a plane situation. If I can get a good fix for this, I'll be good to go. I did submit a ticket in the FT so I'm waiting for someone to response to it. Hopefully with a solution / fix. 

Thank you for your help