[Bf-committers] Blender into a pipeline

François T. francoistarlier at gmail.com
Mon Feb 3 12:57:54 CET 2014

Hi everyone,

I haven’t been around for a while now, but I had the chance to integrate
Blender in a small part of a recent project in my company for the
matchmoving part (we don’t do much of those where I work now). I have seen
all the progress an new sweet features in it, and I wanted to congratulate
you all for the great work.

I never really had to integrate Blender into an existing big pipeline, at
least in a real case scenario. By doing so for this project, I got several
bullet points which might be interested to you. Some might look like bugs
to me when it might just be a design decision, so I won’t fill any bug
report for now.

As for the disclaimer, I didn’t have much time to do a full integration
into our pipeline and didn't had much time to work on it, so you have to
consider this in the following experience I had. But that's also another
good point about blender, being able to work with it in a couple of seconds
after just downloading it, having some file format like fbx which makes
integration easier. I need it to be able to work fast with it, exchange
data with others, work with our infrastructure and in-house tools.
We are using After Effects, 3ds Max, Thinkbox Deadline, FFMpeg, Data
Servers (mostly nothing in local computers), in-house pipelines tools
(shotgun like, lots of automation process, …), Perforce, and so on…
I have been using Blender version 2.9-fd0b104-win64 from 20/01/2014 from
the builder.blender.org

So here they are :

*Start Frame Convention** : *

This is a tricky part and a bit confusing to be honest. I guess we can do
pretty much what we want with the « Start Frame » and « Offset frame ». Yet
that was really confusing to me, and I didn’t trust myself with that.
Our entire pipeline start at 0 for several reasons, which might sounds
logic or not to you, yet the convention is like so. Works better like that
with FFmpeg, AE, 3ds Max,..

The first time, I made sure my timeline was set properly as my Render
I imported the Movie Clip (which was an image sequence starting at 0),  but
didn’t notice the «  Start Frame 0 » in the « Footage Panel ». I did my
tracking and when exported it I had a frame offset happening in Max.

I’m sure all that sounds stupid to most of you and that the solution is
really obvious, again for me not so much. I don’t have time to guess if
what I did is correct or not with the start frame and the offset. I just
need it to work like it should straight away so I can concentrate on the
real work which in this case was the matchmove.

For the second shoot, I decided it to setup my scene correctly defining
what I thought was correct by setting the start frame at 1 et the offset to
-1 with my timeline to 0. Still today I’m not even sure that was the way to
do it, but it actually revealed some kind of bug. The track panel
(magnified image of the tracker) became unusable. If I clicked in it,
Blender was creating a keyframe at the previous frame, and while dragging
the panel didn’t get updated.

All that to say, at the end I came back to the default settings, because I
didn’t have time to figured this out and even so would be sure about it. I
told the 3D guy that he would get an offset in the exported file, so he
would have to move the keyframes a bit in 3ds mas

That is not so good, and makes communication about frame range between 2
application very hard.

So I would suggest to have this defined in the preference. So I could
choose by default that all my projects start at the frame I want (usually 0
or 1 depending of the pipeline) and be sure that blender does all the
tricky stuff for me.

*FBX Export** : *

THIS IS SO NIIIICCCEEEE to have ! Without this, I don’t know how I would
have possibly used Blender for that project since I needed to export the
camera and some objects.
I haven’t check everything, only what I was interested to which is the
camera and it’s animation as well as a few simple objects (cones, boxes, …)
All got exported well except the scale is totally off. I have no idea why !
Both Blender and 3Ds Max are setup in Metrics. But if I create a box of
1,7m in Blender and import it into max, the scene is sooooooo small you
can’t even see it.
I have try to overwrite the importer fbx unit system in Max (trying all
metrics) but I can never get it right. We had to parent all the imported
object to a dummy, and scale it until it looks approximately right. which
is kind of bad when you need to be really precise.
If you need some help with testing, I'm all yours :)
(I believe Max's importer thinks the fbx file is setup in inch, but couldnt
find that in the file. weird...)

*UNC path** : *

Of all, that was probably the biggest pain in the ass. No support for this
is very sad. We are trying to avoid Network Drive for several reasons :
Mostly because if one computer does not have it, nothings works (unc always
also because our render farm does not have it. Deadline have a great
support for Blender out of the box
<http://www.thinkboxsoftware.com/deadline-6-blender/>*) .
I couldn’t use the render farm  because of that, that’s a shame ! Network
Drives only mounts when you are opening a windows session. If you are
running a slave as a windows service, the drives won’t be there.
Yes the farm has some path mapping features to bypass this kind of issue.
But again, didn’t have the time to setup the render farm for that, and we
try to avoid tweaking it in the middle of a production, especially this
kind of features.

Anyway, missing UNC support a lot :)

*Motion Tracking*

Not much to say about the 2d tracker or the camera solver, those are really
INCREDIBLE IMO !!! And I had the surprise to find out about the release of
the weighted track, that was perfect for that project. I needed to solve
lots of 3d positions of objects which I couldn’t track really well and
would have affect the camera solve quality ! that was awesome to have,
thanks a lot :)

Yet here is a few thing I noticed while working with it.

2D trackers Colors :
I love giving colors to my trackers, I love the fact that I can see them in
the 3D view. But it’s sad that the 2D tracker does not get the color. It
remains white all the time in MCE :(
Disabling Track :
hard to guess what it will do. especially when tracking backwards. I
understand perfectly how it works in forward, so I can predict it. but when
I do it backwards, the experience is not quite the same. I would love to
select a bunch of frames and disable it as well (which would creates
keyframe at the beginning and end of the selection)

Tracker Panel :
I understand that what I see in the tracker panel is what the tracker use
to do it’s job, so selecting channels can affect the track and this is
great. But when I do supervised tracking (like tracking frame by frame a
very tiny white dot by hand), I’d like to bump up the brightness / contrast
so I can see it better. It would help me to see what I’m doing. Maybe it
wouldn't have to affect the tracker when it’s tracking by itself.
being able to lock it at the top. I’m scrolling all the time to find some
parameters underneath this panel, (display, tracker parameters, …). but I’d
love to always have this panel on screen no matter what.
Changing the name of the tracker does not update the dopsheet for some

Focal lens :
if you select a camera preset, it get reset every time.
can't animate it this limit a few things. Solving zoom is hard, but
overwriting it could be helpful. For instance :
Shoot A is a wide camera (24mm) it sees a lot of markers
Shoot B is more narrow (70mm) it sees less markers than the Cam A.
Since Blender does not support survey yet a could old technic is to concat
both shoot A and B and give the keyframes in shoot A, so shoot B can
benefits the 3D point solve of Shoot B. Not being able to animate the focal
lens by hand, didn’t let me do that. So I had to align the Cam B by hand
(thanks to the great 3D cursor though)

3D markers :
I wish I could render those ! any shape I’m selecting in the property panel
of the 3D view.
The 3D marker to mesh button, does not create the mesh in the camera space,
so it is not really usable. (and I haven’t find how I can choose a shape
for it (sphere, cones)
The cones shape is not really practical. It’s pivot point is centered and
the tip of the cone is facing up. It would be better IMO if the pivot point
was at the tip of the cone, and facing down.

Create default scene :
I really don’t get this cube in the middle o_O. Is there a good reason for
it ? I don’t see the advantage at all. I would prefer to have it sit on the
floor personally
Having a default material created which does Wireframe + MovieClip
projection by default which I could assign to any object I want would be
perfect !!! I know there is some tricks to create it by using some GLSL
turn on and other stuff, so you only see the front wireframe, yet I can’t
remember how to set it up. I had to do it for that a long time ago :

Compositing default nodes :
handy, but a bit messy IMO. You always have to re-arrange them. A
simpler/alternate pipe could be done if distortion is not solved as well

Distortion :
I managed to work without computing distortion on that project, because it
was very very small and didn’t affect the solve much. Yet if I had, I would
have to re-render distorted plate with some overscan parameter. Maybe it’s
there somewhere but I haven’t find it.

Set as background does not activate it on camera :
It’s too bad you have to go on the camera to turn it on, while the button
could have done it for you

3D stabilisation :
This is really something I’m missing from blender. While stabilizing the
camera path probably could be done via python, I wouldn’t get the new
distorted plate which goes with and this is too bad. Something which was
needed on this project, we will probably do a 2D stab on the final
composite then, but that’s really not the way we wished to do it
Dopsheet :
selection of markers in the view does not update dopsheet selection.
usually the selected marker in dopsheet, does not match the one selected in
the view.

Timeline :
being able to lock markers would be nice.
Don't allow frame to be selected with mouse, I would love that to work with
the arrow key as well !

Those are all the points I did stumble on. Anyway thanks again for all the
great work



François Tarlier

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