Cineversity

I’ve been following this tutorial to learn how to do 3D motion tracking and adding a 3d object in C4D.

At around 18:00, Eric talks about creating a plane, applying the background video as a material on that plane, and using a compositing tag to make sure the plane ends up invisible and is only there to cast shadows or create occlusion.

However, when I render a frame, the plane is showing up as a dark shaded opaque plane rather than invisible. I’m not quite sure what I’m doing wrong, as I’ve followed steps exactly as shown in the video.

Here’s my standard view

Here’s my rendered view.

Hi yngvai,

Thanks for the images, but I work with scene files. Images have so little information about the parameters and setup.

I have recreated this setup in R25, just in case something has changed, as I try not to answer from memory, nor do I like to guess. (See image, …tracked and placed a sphere inside. The black triangle is part of the plane.) Scene files are typically the best answer to return, they work, or they don’t. Simple and clear.

Check if the plane covers the view. Typically it will not. Test this: Set the Motion Tracker Object to invisible, both traffic lights to red in the Object manager for the Motion Tracker, as well for the Background object, if you have one. Delete the Display tag that he suggested for this, and check the settings in the Compositing tag. Render, with a light in the scene!

If all of that is not helping, I can offer you an upload link. (If you like to share it on your own, I open only Dropbox, Amazon, Adobe, Apple, Wetransfer, and Google cloud services. Nothing else. Thanks for understanding)

All the best

OK, I made the motion tracker object and background objects invisible.

I then rendered (I didn’t do the light but you can still see the plane).

Does this mean the plane is covering the view?

I’ve created a Google drive cloud folder with the C4D and video MP4 file if you’d like to investigate it further.

https://drive.google.com/drive/folders/1J8A0ym9JS4VHNKn-gcaIJLz0mS0UwKP6?usp=sharing

Hi yngvai,

Thanks for the file and the extra work with the drive. Very much appreciated.

Here is a setup without any tracking, so the focus is on the problem, as it has nothing to do with the tracking. I have used just a still from your shot and placed it into the scene. I have added a screenshot, so you can see what I saw. You need light, and you need to render it.
For the example below, just render the camera view.

https://www.amazon.com/clouddrive/share/sQc7FfQG7MuOSuF074zH0uT56fRWKhO8I1VWisgcCYE

BTW, you have certainly picked one of the more challenging shots to track (So many moving parts in it, and fast pans, and no lens profile, which makes it even harder.)

Enjoy your weekend

Thank you for your help. I think my point of confusion from the tutorial was Eric had clicked “Render View” but hadn’t rendered it (I thought he had), so I thought when I rendered without the light source it should just look like the original video.

Yes, it was a challenging track. I had originally tried the track in AE but couldn’t get a good one. I created a number of manual tracking points to help out the C4D tracker. The very hard pan at the end will be cut out of the final video anyway so I didn’t worry about tracking the very last part.

Thanks for the reply, yngvai.

Yes, I tracked it, and the main work was to delete the tracker caused by the moving people. Since they walked nearly all with the same speed, the amount of moving vs. static information was nearly the same. That needs manual work.

When you shoot something like this again, I suggest walking a short distance (while the camera continues to roll) to have more parallax in the image. The walk could be before, while, or after the shoot. As much movement as possible, as that will give more explicit information about where the camera is.

A good lens profile will help here as well, besides knowing the camera’s focal length.

All the best

Thank you. When I originally shot this footage, I had no plans of doing anything with it…just a neighborhood parade that my daughters were in. But then I got this idea to composite a walking skeleton doing the YMCA (I had another thread in the forums asking about that which you helped me with) just for fun, and I thought it would be a fun little project that would help me learn C4D as well as learn to create more realistic renders with Redshift (Element 3D in AE, which I used to do another animated composite skeleton project, doesn’t do physical based rendering). So I’m in the middle of that whole process right now.

You’re very welcome, yngvai.

Yes, I know how one thing leads to the next. You have an idea, and you do it, which is the perfect base to turn information into knowledge and knowledge into skills. You will gain so much from it.

I hope you enjoy the ride, and let me know if there are any obstacles (please in the Q&A forum). I’m happy to share whatever I can.

When I give tips here, please always know that I write in a forum. I never intend that my tips show up as an evaluation of what one artist alone would need. I answer typically a little bit broader or perhaps even basic.

ENJOY!