How to export 3d camera from Nuke to Blender?

Hello!
I have a video in which the camera glides along the ground. I want to put leaves, made in Blender, on the ground in this video. To do this, I want to export an animated camera (created using 3d tracking) from Nuke to Blender.

Can anyone explain to me please how to export the 3d camera from Nuke to Blender?

Thanks in advance!

Hi Cheburash.

Let’s see if we can get this sorted out for you :slight_smile:
After you’re done camera tracking and you’re ready to export, click on ‘create scene’ in the camera tracker. Next pipe your 3D camera into your ‘scene’ node if it isn’t already done for you. Now create a ‘write geo’ node and pipe your scene node into it and choose file type “FBX” “Alembic” etc… not sure what version you’re using, my version is a bit older and doesn’t allow me to export alembic or DAE(collada) so you might have to see which one works for you. You also may need to check off “geometries” to get your nulls / 3d points into blender as well.
If you’re using a new version of Nuke(lucky you!) you might be able to just export straight from the camera tracker.
Hope this helps!

Thank you very much, Rigby40! This is very helpful! :slight_smile:

And I wanted to ask if there are any tutorials about how to import 3D tracking in Blender (not how to do 3D tracking in Blender, but how to import ready-made 3D tracking)? Because my tracking looks good in Nuke, but it seems to me that in a blender camera changed the angle of view on the point cloud.

Hi Cheburash,

 Glad you found it helpful. I'm not sure how to remedy the issue you're having with the point cloud. Once in Blender, is it the camera that changed angle or the point cloud(or scene) that changed angle? I think I've had the same issues before but I didn't have as many export options at the time using Nuke V6.3 I was hoping that you'd be able to get something decent with the other export options that you have if you're using a later version :) It might also have something to do with properly orienting your 3d scene in nuke, which as far as I can tell isn't very intuitive and surely doesn't have as good of tools for orienting your scene as other tracking applications.
 Do you have PFTrack or Boujou? I made a tutorial on how to export camera tracks from PFTrack/Boujou into Blender without a hitch :)

If we can figure the camera or scene changing angle bit in blender I’d be happy to make a tutorial on the process for anyone else who runs into this issue.
If I have time at work today, I’ll try to play with some footage and see if I get the same issue.

Hi, Rigby40!
Thank you very much for your time! :slight_smile: I work a lot in Nuke, so it’s important for me to learn how to do 3D tracking in this program. But I would be very interested to see your tutorial! Where can I see it?

I worked a long time with the version NukeX6.0v1, and recently started using version 9.0v3, so for me, too, in the new version many unknown settings :slight_smile:

The fact is that after export, the camera changes angle of view on the point cloud.
This becomes clear if we add a cube to the scene. Here are a screenshots:

Nuke:



Blender:

And here is how the scene looks in Nuke. This is a very simple scene:


And P.S. One more question: points have something like guide lines, what is it and whether it is possible to disable them? Direction of these lines is the same as the direction of the global axes.

Once again, thank you very much! :slight_smile:

Perhaps I have a problem with the tracking itself? This is one of my first experiments with 3d tracking, maybe I made a mistake.

Hi Cheburash,

No problem I enjoy these technical hurdles :slight_smile:
It looks like the same problem when I tried exporting from Nuke. The camera rotates a bit and/or changes in FOV.
Hmm what file type are you saving out? Can you upload the file of the tracking data? I’d like to take a look at it in an editor and see if there’s something fishy going on although I’m just getting used to opening files up in an editor so i may not be able to see what the problem is, but it doesn’t hurt!
And about the 3d points / nulls you’re seeing. You should be able to disable them in blender although it’s probably better to just scale them down a bit instead as they are very useful to use even if you do have a point cloud too. Make sure to scale them down by their own origin otherwise they will scale to the group origin and move out of place.
I believe they come in grouped so you’ll have to look in the outliner to find them. If I was at home on my own machine I could probably tell you exactly where they live :slight_smile:

I don’t think it’s a problem with your tracking. Even if your solve was extremely terrible, you should still be seeing exactly what you saw in nuke and not a camera out of rotation!

Here is a link to my tutorial:

You’ll need Maya as well to make it work, that’s the one catch.

I love nuke’s camera tracker but it doesn’t have half of the tools that PFTrack does. The scene orientation tools that PFTrack has really make things easier. Not to mention all the different file types that you can export.

Thank you, Rigby40! I am very glad that I met you on this forum! :slight_smile:

I used fbx format, here is the link to download the .fbx file: https://drive.google.com/open?id=0B5frx8D5eNByaHowTmlrS1lLTnc&authuser=0
The .nk file: https://drive.google.com/open?id=0B5frx8D5eNByMzdpbGd5dC1WRFE&authuser=0
and original video (this is a stock video): https://drive.google.com/open?id=0B5frx8D5eNByVFo3d1FLTU1jbkE&authuser=0

I used Google drive, if there is another special service for the transfer of such files, I can send you files through it.

And thanks for the tip about the points, it worked! :slight_smile:

Happy to help!

I can’t open this file now, at work we have Nuke 8 but it’s not properly installed on my computer so I will have to wait until I get home but could you send me a screen grab of your node graph in nuke? I’d just like to see which nodes are where.
Also, can you export a collada or .dae file or does it not have that option? I always seem to have issues getting camera tracks via .fbx into blender. I’ve had far more success with .dae collada files.
Let me know!

-Rigs

I just wanted to clarify that I did not export cube from Nuke to Blender, but I created it in Blender, with the same axis as the cloud of points to show that the camera is looking at the cloud from a different angle.

Sorry, I can not write for a while, here’s a screenshot of the node graph, and I’ll send the rest later.



Thanks!

Hi, Rigby40! Sorry for the delay, one of its causes - the difference of our timezones :slight_smile: Unfortunately I don’t have the necessary files yet, but tomorrow I’ll try to send them. Thank you very much for your help and have a nice day! :slight_smile:

No prob :slight_smile: I already looked into Nuke 8 at home and it looks like you only get a few options to export and I don’t think any of them will work easily with blender. Not sure what to do about it at this point.

Thank you very much, Rigby40! Thanks to your lesson I made 3d tracking in PFTrack and export it to Maya and then finally to Blender! It is strange that when I exported .dae file from Nuke in Blender such errors occur. But your method works great! Thank you! :slight_smile:

Awesome! I’m happy to hear that it worked out in the end.
I only track in Nuke if I’m going to stay inside Nuke just to avoid problems like these but the PFTrack to Maya to Blender route always does the trick :slight_smile:
Have fun tracking!

It was quite simple tho, in order to achieve it and have the corrected matrices you have to change the camera’s Delta Scale as also animation offset when importing the FBX.

Import FBX to Belnder

  • No Manual Orientation
  • Sale (scene) : 100.0
  • Animation Offset (0 or disabled, else it will be moved 1 frame to the right)

Camera Properties

  • Camera Delta scale [x:-1 y:1 z:-1]
  • Rotation Mode (XYZ Euler)

normally this should work out of the box.

good luck