Render an FBX file

[saundersj7PB45]

Hello.  I have imported an FBX file of a motion capture that was exported from Motive (Optitrack motion capture camera software).  I was able to also import another model from a free model site and add the FBX motion capture file's movements to the model.  I did that by selecting both at the same time and then binding the skin.

The next step is to be able to render the current file so that it can be exported to a program like Nuke and added to an existing video scene.  I found the video below about rendering an animation file that had been imported into Maya.  But, I can't find anything about rendering an FBX file.  There's a piece in the video below about setting up a camera for rendering.  But, in my file in Maya, I can't figure out how to connect the FBX file's camera to the rendering process.

https://www.youtube.com/watch?v=vxvIUBeTkL0&t=3s

Do I need to combine the two files together in Maya before rendering?  Or, does binding the skin do that?  And, once rendered, what will I see once I export the file and then import it into a program like Nuke?  Will it just be the character with the motion capture movements?  Thanks.

[dave.cooleyVKJNJ]

A few things about your description. 

1. You are asking how to render an FBX file. Do you mean to ask how to export the maya scene back out as FBX with the character's animation? that requires you to export the fbx file and animation keys. (not "render")

2. If you really mean "render" = image sequence to use in Nuke or another edit/composite program, then you need to render out your image sequence as png, exr, or whatever you prefer. maya can render in Arnold using Render Sequence.

3. Your question about cameras. if there is a 3D camera already built you are trying to match motion to, then you will need to extract the motion data of the camera and import it into Maya before rendering. If you already have the 3d camera from the FBX file, then you need to choose that camera as the render camera in the render settings.

[saundersj7PB45]

I was able to get the footage from Maya into Nuke and composite it over another video file.  One thing I found out is that the character doesn't stay on screen the whole time.  I need to do a little further research as to how to set up the cameras in Maya so that they are viewing the character at all times.  

Do you have any suggestions on tutorials I can watch to learn about that?  I've used cameras in Unity but am not real familiar with setting them up in Maya.  Thanks again.

[dave.cooleyVKJNJ]

this one is a little old, but i made this for my students years back to show them how to control the camera along a path and how to control where it's looking. 

may be more than you need, or just what you're looking for. 

https://youtu.be/WnpssCUY274?si=xhR_6GjahmN9j6xI

[saundersj7PB45]

Hello again.  I started watching the tutorial video that you shared about setting up the motion path for the camera in Maya.  Does it matter what view I am in when I draw the motion path and then attach the camera to it?  I am in perspective view in the attached video but it looks kind of like a 3D view.  I have a video attached to illustrate.  

Also, it seems like the animation moves at a normal rate if I set the frames per second to 75.  Setting it to anything lower makes it move too fast and setting it higher makes it move too slowly.  When I export the motion capture from from Motive, it is at the speed it was filmed at with the motion capture cameras.  Is it the case that the frames per second will usually have to be adjusted in Maya to make the animation move at a believable rate?  Okay, thanks again.

[saundersj7PB45]

I guess one other question would be how I would draw the motion path of a moving item.  In the video, you show drawing a motion path between objects that don't move.  Thanks again.

[saundersj7PB45]

I'm working through your tutorial to see if it will work for what I'm trying to do.  I am trying to zoom out the view on the hypergraph hierarchy and am not sure how to do it.  I also can't get the camera to come out of the group as shown at about minute 10 of your video.  Any help would be greatly appreciated.  Thanks.

[saundersj7PB45]

I was able to zoom out but I still can't get the camera to move out of the group with either the trackpad or middle mouse button using a mouse.  

[saundersj7PB45]

Using a Windows mouse on a MacBook allowed me to move the camera out of the camera group in the hypergraph hierarchy.  It wouldn't work with a Mac mouse.  I'll continue with the tutorial and see how it goes.  

[dave.cooleyVKJNJ]

Hello, I’ve been out of town and I see you had many questions.

First, props for not giving up and pushing forward.

Here are the answers to the questions you asked in order.

From Message 5 of 9:

I usually draw the motion path in the view that best fits. So, for something that moves along the X and Z axis, I would look at it from above (TOP view). But if it’s more of a lateral move with ups and downs, I might choose a Side view.

It’s not the frame rate that changes the speed of the camera or the animation. There are options in Maya’s preferences that let you “play every frame” or “play real time”. If your computer is very powerful, or your scene is very simple, it will play as many frames as it possibly can if it’s not limited.  I prefer to set these options as “Play every frame” but set MAX playback speed to 24x1.

If the motion capture you used was recorded at 24, 30, or 60, you may have frames inbetween the existing frames in the timeline. So, for example, if you brought in a 60fps animation, there are actually frames tucked between the frames you can see. This was an issue I experienced years ago.

Message 6 of 9:

 Answered above, but copied here: if you want to animate the actual motion path, you would need to rig the curve with deformers of some sort. This could be done with clusters on each vertex point, or you could try a wrap deformer on an object. I would personally make the motion path static for the first go to make sure you are comfortable with the whole process. Then feel free to play with more advanced options.

Message 7 of 9:

Sounds like a mouse issue. You should have a 3 button mouse since Maya relies on those buttons a lot. A wheel with the middle button is easy to scroll-zoom in and out.

Message 8 of 9:

You can also unparent object from a group by Shift + P. the way I told my students to remember parenting order is “pick up the baby, give it to the parent” and to unparent, it’s just select the object you don’t want in the group and capital P to pull it out.

Message 9 of 9:

Yeah, there will always be easier ways with a 3 button mouse.

[saundersj7PB45]

Thanks for the reply.  Changing the speed to 29.97 fps and setting that as the max playback speed makes it look pretty realistic in terms of how fast the motion capture animation moves.  24 fps is a bit slow.  

In terms of animating the actual motion path so the camera follows the model, I don't really understand your statement below. 

"If you want to animate the actual motion path, you would need to rig the curve with deformers of some sort. This could be done with clusters on each vertex point, or you could try a wrap deformer on an object. I would personally make the motion path static for the first go to make sure you are comfortable with the whole process. Then feel free to play with more advanced options".

I'm basically looking for a simple way for the camera to be able to follow my model's motion capture path so the model remains visible the whole time.  Some of the tutorial videos I found just show the camera having the moving object as a parent.  But, because I bound the skin of the motion capture file and the model that is doing the motion capture movements, I'm not sure which object to connect the camera to as the motion capture skeleton and model are still listed as two separate items in the outliner.  The first screenshot shows my motion capture file (Skeleton) and the second my model (rp_eric_rigged_001) in the outliner.  

This is one tutorial that I was following.  I was focusing on the first part with the character walking across the screen.  In this video, there's only one character serving as the parent to the camera.  

https://www.youtube.com/watch?v=Uvitjgm81HE&t=290s

I guess one other question would be if it is just easier to maybe create a circular motion path that would essentially move around the motion capture model in a way that keeps it in on the screen.  I don't need the camera to precisely follow the model.  I just need it to stay visible on the screen.  Thanks again.    

[dave.cooleyVKJNJ]

ok. so, the model's rig is already connected to a curve by a motion path in Maya?

You can parent the camera group to the root skeleton joint hierarchy (or top group depending how you built it). Basically whatever the motion path is controlling of the character rig, put the camera group under that. 

[saundersj7PB45]

Okay, I might be in business here.  I just connected the camera group to the skeleton, which is the actual motion capture portion of the project.  It seems like the camera is staying with the model now.  Does it look right to you?  I can export it as an image sequence and import it into Nuke to see what it looks like over another video.  

Now, I have to go back and review that process again.  LOL!  But, I should be okay.  

[dave.cooleyVKJNJ]

Looking at this animation, I'm not seeing any actual "motion path" being controlled by a curve.  I think the main point of confusion was using the term "follow a motion path" because in Maya, that is a very specific set of steps for animation. 

In traditional animation language, a motion path is simply the area an object travels in a given timeframe. 

The animation's simply using keyframed positioning. I wouldn't call this an actual "motion path" that we create in Maya by creating a curve and choosing to "attach to path". 

I would actually hand-key the camera to follow the action of the character. You have much more control over it that way. Don't over animate it. 

Major suggestion, be sure to create a new camera and position & rotate it manually by looking at it, NOT through it.

[dave.cooleyVKJNJ]

the cube represents your character. 

Create a new camera and move it around using the persp view. view the camera's view the way you would use a real camera's screen.

[saundersj7PB45]

Here's what it looks like in Nuke.  The output of the motion capture is smaller this time than the first time I did it where it was going off the screen.  But, it stays visible.  I'll have to review your most recent email and try some of those techniques if I want it to be more precise.  But, it works okay for now.  Thanks again.

[saundersj7PB45]

I seem to have a general solution to the camera issue.  It doesn't make as much sense for me to to do the motion path as I really just need the camera to be in a position to be able to see the figure for the entire time.  Since I'll be compositing it over another video, it might look odd if the camera is moving around the motion capture model while it's over the other video.  But, either way, I was able to get the camera to connect to a curve or have it in a position to see the model at all times without moving.

On a separate note, I have had some success binding the skin of some of our motion capture files to at least one model that I downloaded from the Internet.  You can see that in one of the attached videos.  That video also has the camera set up so it can see the model at all times.  

In the other video, you can see where the bind skin process gets a little wonky.  I've found some videos that show that you can move individual parts of the skeleton to try to match up a little better with the model when binding skin.  But, it still seems wonky.  It's even worse when there's a model that is a different build such as a Super Mario model versus my motion capture skeleton model.  I'm just wondering if there's other tutorials on binding skin when the model is a different build than the skeleton.  Thanks again.