Mend Me Blog » blender

Compositing scene 1

Philip — Wed, 29 Oct 2008 03:56:23 +0000

Figured out and implemented render layers – now working through all the issues that come with the privilege of splitting one’s renders up, namely character foreground/background overlap. Apparently this is solved with the “Zmask” render pass. I’m having issues with the layering as the butterfly goes both in front and behind the trees. I posted and got some good answers, and eventually worked out what I was doing wrong. Also it seems my approach to nodal compositing was a bit off as this one fellow points out, and subsequently made me wonder why I ever did it this way to begin with, that I only need one Defocus (DoF) filter at the end of the chain rather than on each layer.

Got depth of field working so that it tracks the distance of the butterfly at all times.

Z-mask problems

Scn 1: butterfly liftoff

Philip — Tue, 28 Oct 2008 02:56:51 +0000

Seems that if I have automatic keyframing on when keying the camera it goes crazy with rolling rotations when I use the free-look camera mode. Solution is to turn the auto-keyframing off and manually insert the keys after using the free-look cam placement.

In order to make use of the NLA animation strip sequencing I needed to create the following short animations:

Leg blending

Sway to left
Sway to right
Hanging centre

Wing flap

Full flap
Half-way flap
glide position
rest position

These strips became the toolkit for “decorating” the core animation of the butterfly. This really worked well with the whole start with broad strokes and work your way down approach to creative endevours.

Action editor

Philip — Thu, 23 Oct 2008 00:08:00 +0000

Finally worked it out. The first point to absorb is that it only affects bones whereas objects have their keyframes dropped into the Non Linear Animation Editor (NLA). This was very confusing for me at the start but eventually it became apparent that the action editor creates timelines that can be arranged and blended in the NLA so one has to be very aware of which “strip” is active when moving things around (with autokeyframing on) as keyframes can end up in the wrong strip which then produces unexplected results. This method seems powerful, for example the entire first scene with the btterfly flying and gliding was very little detail animation. I animated a 5 keyframe strip of the wings flapping, 2 keyframe strip of wings in a gliding position, and that’s it for the wing movements – the variations were created by blending in and out of duplicates of these strips set at different playback speeds. So when the 2 frame glide strip is blended over a flap the wings ease into that gliding position, but because I only keyed the main bones in the wings the flickering tips aren’t affected and so continue to flicker. The walk up the stalk was of course animated all the wa though.

Matte painting transparency

Philip — Tue, 21 Oct 2008 05:29:00 +0000

After experimenting with the hair particles in Blender I wanted to use the painting from the animatic for the grass in the first scene as I could not get hair particles thick enough and with the same character. After looking through numerous tutorials I could not get partial transparency to work on the images assigned to planes – it was either 100% or 0% which leads to ugly jagged fringes. Eventually I found the answer (which is probably pretty obvious to someone familiar with 3D work): you have to pre-multiply the alpha on the image. Pressing the Premul button after loading the image makes life prettier. It is annoying that a lot of documentation seems to miss a critical point like this and leads to much frustration.

There also seemed to be two ways to go about making this material setting. The one where the alpha slider affects the transpanecy of the opaque parts of the image seems the most logical. The other makes the material’s general alpha slider effect the degree of the alpha. This seems less logical to me as the general alpha should effect the transparency of the whole object not the texture.

Mesh to armature – old or new way?

Philip — Wed, 15 Oct 2008 07:47:00 +0000

Seems in Blender that there are 2 ways to attach an armature to a mesh: the “old way” being parenting the mesh to the armature and the “new way” being adding an Armature Modifier to the mesh. There seems to be confusion over the benefits of using the new way. I have been confused not so much that the new way is cleaner and suits the overarching workflow of Blender better but with all the facets that rigging encompasses (weight painting, vertex grouping etc). For instance eyeballs as a separate object could be parented to a bone whereas, as far as I can see, if you apply the Armature Modifier to the eyes you then have to link the vertices to the bones – many more steps.

The “new feature” of Bone Heat Weighting has only confused me more as the workflow for that seems to include using the “old method”. So if they are shifting paradigms why are there new (and attractive looking) features for the old method.

Links
http://dreamsgate.wordpress.com/2008/06/09/rigging-bone-heat-weighting/
http://www.blender.org/development/release-logs/blender-246/skinning/

Armature versus parent

http://wiki.blender.org/index.php/BSoD/Introduction_to_Rigging/Preface:_Rigging_in_Blender

As shown on this page the “new method” is “better” which is somewhat unhelpful especially when viewing the “new method”s feature page (http://wiki.blender.org/index.php/Manual/PartII/Modelling/Modifier/Armatures) which doesn’t really list the aforementioned features that make it better than parenting the mesh. Another thing that I still don’t understand from the instructions here is why one would need to “give the mesh Copy Location, Copy Rotation and Copy Scale constraints, all targeting the armature” – isn’t the modifier supposed to take care of that?

New Blender release – 2.48

Philip — Wed, 15 Oct 2008 05:11:00 +0000

I always welcome an update to any software but what has this new version of Blender got to offer that is immediately relevant to this project?

The shrinkwrap modifier looks like it will be useful for modelling the lil-boy’s clothes
The sun lamp considering I have many outdoor scenes
The sky parameters, again because all my scenes are outside.

ATI just got better with 8.8 drivers

Philip — Wed, 10 Sep 2008 06:22:06 +0000

The good news is that the recent ATI driver (for 4870 card) update seems to have fixed my Blender modelling issue – it is now possible to USE the program again. It is probably pretty silly (like 16-year old schoolgirl silly) but I was pretty chuffed to get responses from Ton Roosendaal on the Blender bug tracker report that I submitted on the issue. He is one of the founding members of the Blender institute and responsible for putting the open source movie projects together.

Bad news bears: Ubuntu Studio is stupid in that they don’t give you the source code for the kernal nor does it seem easy to find… well I haven’t found it yet! I managed to find ATI drivers for linux but can’t install them because of a political (that is right not a technical one) blockade in linux where it will not let me add proprietary code to the source code i.e. the ATI graphics card driver. Apparently I need to alter the actual source code to make it possible to do this. Although I can understand how this could maintain some quality control throughout the community it is a royal pain in the arse and seems a bit pigheaded. Like the GIMP having a not-in-my-backyard complex that prevented them from making a brush resize slider for about a decade.

So when I can be bothered (need is less now that Blender works in Vista with ATI) or start rendering I will go grab either vanilla Ubuntu or Fedora and use that. As far as I could tell the “low latency kernal” of Ubuntu studio in of use only with sound production which doesn’t apply to me – I’ve got Logic, Protools, Cubase and Audition.

Relative file paths

Philip — Mon, 08 Sep 2008 06:15:25 +0000

After happily ordering my project directory I discovered that my animatic was completely stuffed – “what’s this?!?! Absolute file paths!? Damn you!” So remember kiddies that there is an option in the settings pull-down (mouse to the border of the top menu bar and you will be able to stretch it to reveal hidden stuff) File Paths > Relative Paths Default. Unfortunately this then only applies to new links created so I had to go through and relink all the images in the animatic to the new ones.

It would not of been too bad if the Animatic directory wasn’t such a mesh mess [ha! too much modelling!] to begin with: at the beginning I thought (for some stupid reason) that it would be best to use .jpg exports as the animatic images. Later I discovered that it was much cleaner and easier to modify if I linked the actual .psd files in the sequencer.

Yes I tried to Remap Paths (SHIFT-RKEY) and although that always looked promising, it never seemed to do anything at all. CKEY saved my life: you still have to do it manually but you can exchange the current non-existent images with the correct ones rather than building the entire sequence again *shudder*.