another year over, a new one on the way!

Happy Holidays!








Film Update:
I've stopped rendering the film in order to work on my demo reel. I'm looking for a job as an animator (using XSI in preference ;o). If anyone knows of an opportunity please email me : tiger at smokingmoose dot com.

tweaking final gathering settings

My small render (250x141) is completed and composited, sent out for feedback and feedback received. Between the time I sent it out and received feedback I started the final res render (1280x720) and discovered to my horror that the final gathering pass was taking up to 23 minutes a frame to render. I went back in to the render settings to tweak them.

Here is a resume what Dave Lajoie wrote in a pdf about final gather settings (I think the pdf is from XSI 3.0 release -- some of the settings are no longer named the same -- you can get it here) :

"So to recap on FG accuracy and radius, [...] here are the different combinations and permutations:
• When Radius is small (0.01-0.2) and Accuracy is high (1000-3000), the render speed is the slowest but the render quality is the best. Usually these settings are suggested to remove FG flickering. Since each frame contains a lot of FG samples, it is suggested that you rebuild the FG map at each frame. Otherwise the FG map file will grow too rapidly and the renderer will run out of memory.
• When Radius is Large (1-100) and Accuracy is High (1000-3000), render speed is a little faster. This combination is perfect for smoothing out the FG result, giving the rendered image a more blurry effect. Again it is suggested that you rebuild the FG map at each frame since the FG accuracy is high.
• When the Radius is small (0.01-0.2) and Accuracy is low (100-500), the FG result is poor. I suggest that you use this combination only for preview purposes.
• Lastly, when the Radius is large (1-100) and Accuracy is low (100-500), the FG settings are ideal for an Image based lighting pass, as long as the image used for the lighting pass doesn’t contain too much high frequency detail. It is strongly suggested that you blur the image that you use for the image based lighting pass, since this allows you to use low Accuracy and a large Radius, which will, in turn, save precious rendering time.

Very important to remember:
If Radius is small, Accuracy needs to be high.
If Radius is large, Accuracy can be lowered."

For my smoking moose purposes I chose the 4th option - large radius and low accuracy using image based lighting. The min radius is set to 20, the max to 50, the accuracy is set to 100 and the filter is set to 1. I'm using a constant image for the image based lighting pass as well as a few constant color cards to bounce rays off. Since I'm also rendering a dirtmap pass I can get away with the larger radius and lower accuracy.

Also, Dave's pdf mentioned that high frequency textures should use lower radius and higher accuracy -- the braided rag rug is a very high frequency texture -- this could explain the high render times. So I used a trick mentioned in the pdf:

"Another trick which can save a lot of time is to use a ray_type shader, which allows you to use two different rendertrees, one for camera rays and one for Final Gathering rays. With this approach you can use a simpler rendertree to remove high frequency from the surrounding object’s surface."

The FG render pass is down to 2 to 6 minutes per frame! Of course the other passes also take time, so the total combined render time is higher than 6 minutes, but it's still a lot less than if I had continued rendering the FG pass with low radius and high accuracy!

The "rebuild" options refer to the Final Gathering Map and have changed since the pdf was written. I'm using XSI 4.2 and the options I have are:

• Overwrite
• Append
• Generate

Since there my film has a lot of small camera moves and a lot of characters moving around, I've set this to append. See chapter 15 of the Shaders, Lights and Cameras user guide for the details.

Thanks to Dave wherever you are!.

Now on to fixing some of the stuff I received feedback on.

clouds, emitters and partitions

Although it is possible to have more than one emitter per particle cloud, it might not be a good idea if you need to separate the emitters into different passes. It is the cloud that matters in the partition, so even if an emitter is not in the partition the emission from it may still appear in the render because the cloud that it belongs to is in the partition.

rig from guide and remove all animation any type do not mix

Here is something to remember if you are using Rigs from Guides. These rigs use Scripted Operators to control the upvector - the scripted operator (as well as any constraints or expressions) will be removed if you use the Remove Animation > from All Parameters, Any
Animation Type command from the Animation panel. Which will result in the rig no longer behaving as expected - i.e. if you use the Remove all animation command and then try to rotate the chest, the upperbody will not follow.

I was not able to recreate the scripted operator and had to regenerate the rig from the guide.

To avoid this, only remove animation from the specific transform (position or rotation) rather than all!

my smoking moose film teaser

The film is being rendered ... it's gonna take a while. It took me a long time to get the settings right and the passes right. I almost have a complete version of the film at a small resolution, that I can use to finish the sound edit and the music while the film renders at full resolution.

Painting is easy ...

"Painting is easy when you don't know how, but very difficult when you do."

Edgar Degas

Why re-using a ptype may not give the same color results as the original

Remember that lighting affects the look of your particles, so if you are reusing a ptype with different lighting, it may look completely different. If you are doing this in the same scene and the emission is just not in the same position as the original, you can add an exclusive light to that particle cloud so that it can look the same as the other, but the rest of your scene won't be affected by the additional light.

animate particle color at frame 1 if you're using age% as the animation reference

This is probably obvious if you think about it, but since I just spent a couple of hours trying to figure out why my particles were rendering grey and not the animated colors I had set, I figure it's worth blogging. If you are using age% animation reference for the particle color, make sure the colors are animated at frame 1. Otherwise depending on what frame you are animating the emission at you may only get the last color of color animation.

texture editor + extended component selection mode don't mix

Here's a tip when working in the Texture Editor. If you like to work with extended component selection mode turned on, you should turn it off when working in the Texture Editor. When it is on, it keeps adding to the selection so that when you are manipulating sample points you may actually be manipulating many more points than you are aware. So if points on what you believe to be unselected clusters seem to be moving, check to make sure that extended component selection is turned off!

displacements

... something to remember when applying a displacement - increase the subdivision on the object to see the "real" effect, otherwise what you see in the render region will not be as defined as you expect it to be.

more smoking

The volume shader didn't work out on the moose's moving cigarette... it looks great on a static object but looks strange on a moving object. I've reverted back to using particles. I've got a decent looking smoke emitting from the cigarette ash, using the beam type for the shape. I've added a vortex (child of the ash) to give the stream a bit of variety. It doesn't look convincing on a static frame but it does look pretty good in movement.

For the exhaling smoke, I've setup events to billow the smoke and have gravity, turbulence and vortex affecting the particles.

smokin

Lately, I've been spending most of my smoking moose time working on the smoke effects. Currently focusing on making the moose smoke his cigarette. I've analyzed cigarette smoking videos and films (from getty images and from some DVDs I have .. Ryan has some good examples of cigarette smoke). When smoking a cigarette there are 3 different types of smoke:

1. the smoke that rises from the tip (end) of the cigarette as it burns
2. the smoke that rises from the filter of the cigarette after an inhalation (most likely this is the smoke that has been pulled through the cigarette but didn't get inhaled)
3. the smoke that the smoker blows out

For now, I'm ignoring the 2nd type of smoke and just focus on the first and last .. if I hadn't have analyzed the video footage, I'm not sure I would have seen this 2nd type.

I started experimenting with XSI particles and then adding effects in the fx tree. This could work well if I could pin the start of the particles to the end of the cigarette (in theory this is possible using the tracker, but I'm using XSI 4.2 and the fxtree tracker crashes XSI... This is fixed in 5.0 but I'm a bit weary of upgrading at this point in production).

Currently I'm experimenting with the volume shader for cigarette smoke. You can get a good head start on this by using Holger Schonberger's preset downloadable from http://www.edharriss.com/shaders/shaders.htm. A small tip about using the volume shader technique - the smoke rises straight up until it hits the center of the object - so to control when the turbulence starts in the smoke, edit the center of the object.

For the exhaling of the smoke, I'm currently experimenting with the smoke explosion particleop.

happy holidays

more smoking moose stuff to come in the new year....

Animating Characters

With the characters skinned and rigged I've been animating and animating and animating!

I use a mix of animation methods, but before I do anything I act out the motion with a stop watch. Actually, before I do that I run through the motion or sequence in my mind until I can see the character performing it, then I act it out with a stop watch. This can take a long time, because I stop and write down the number of seconds for each part of the movement so I end up acting it out a number of time. Once I have the timings down, I may roughly sketch the poses in my sketchbook, or I might jump right in to the scene. I also rely a lot on reference material from the web or from real life. I spend a lot of time looking at the movies on gettyimages or the bbc motion gallery. Of course if the scene has sound, I will use the audio as reference.

I usually start with simply animating the position and orientation of the whole character, followed by the hips, then the feet, the upperbody, then the arms and head, working with poses and using next/prev keyframe to check the pose changes. When I think the poses are good I'll do a quick hiddenline render to see it in real time. I usually leave the secondary animation until all the primary animation is done and things are looking good.

I set the fcurves to be created linear by default rather than spline. Of course for things that absolutely need spline curves, I'll switch the curves back to spline immediately. The canary's swing, for example, absolutely needs a spline curve. For all other curves I will decide at the tweaking stage how to edit the curves. For some I will manually set keys to control the ease-in and -outs, for others I'll just switch the curves to spline.

The most unusual thing I've discovered recently is that birds walk in a backwards human tip toe. Take a look at any of the bird quicktime movies on gettyimages and play them backwards, you'll see what I mean.

Rather than re-write what has already been written about animation by those more qualified than myself, here are a number of valuable online animation references:

Character Animation articles from Siggraph
Spline Doctors blog
Keith Lango (blog, short films and tutorials)
Shaun Freeman (collection of animation tips from various sources)
Carlos Baena (collection of animation tips from various sources)
3D Ark


The other things that help me are reference books and videos! I've got the Illusion of Life and the Animator's Survival kit within hand's reach. But nothing starts a good day of animation like watching an animated short (I keep Warner Bros, Pixar, Aardman, and Rocky & Bullwinkle DVDs and tapes close by).

Enveloping (skinning) tips

> use the default values for the envelope (2 skeleton objects and distance based);
> apply a smooth (leave the default values);
> animate or move deformers to see where the weighting needs to be improved;
> sometimes it will be easier to select the points and reassign locally to the deformers they should be assigned to;
> painting weights works well for large area revisions but is a bit difficult to control the accuracy for smaller areas;
> for the final tweaks you may need to edit individual point weighting, selecting a bone with the weight editor open and scrolling through each point works well (although a bit tedious);
> when you are happy with the enveloping, freeze the envelope modifications and save a preset (from the Envelope_Weight property page, located under the Clusters > EnvelopeWeightCls);
> make sure to occasionally check a render region while you are enveloping, or render a short animation sequence, creases in the skinning may be seen in a mental ray render that you don't see in hidden line or shaded.

If you need to add a bone or other deformer to the rig / or if you need to add points to the geometry:
> save a preset of the envelope weights;
> return to the default skeleton pose;
> mute the envelope;
> add the deformer or the points to the geometry;
> set the envelope (leave "automatically reassign envelope" toggled off);
> turn the envelope back on;
> load the preset;
> reassign the points near the added deformer as necessary or in the case of adding points to the geometry reassign the newly added points to the nearest deformers.

Preparing the rig and the character's geometry for skinning/enveloping

- create a shelf of tools or a synoptic view to make it easy to select the rig objects;
- test the skeleton/rig and its hierarchy to make sure it moves the way you need it to;
- make sure all bone joints are slightly bent (to ensure the preferred angles are created correctly);
- make sure the shoulder bones extend slightly past the shoulder (to avoid enveloping problems in the armpits);
- make a group of all the deformers (it will be easier to pick in one shot rather than trying to pick each deformer);
- select the skeleton hierarchy in branch mode and set neutral pose (this will zero out the SRT values and make it easier to manipulate);
- open up the kinematics ppg for each bone and make sure the order of rotation is set correctly;
- add transform setups to the objects so they'll switch automatically to the correct transform tool on selection (remember to switch to additive mode for rotations);
- store a skeleton pose of the rig in its default pose (make a reset pose button on the toolbar/synoptic view)
- make sure that the geometry has enough points where the joints will bend;
- freeze the modeling of the geometry;

Create a Skeleton Rig from the Biped Guide

Using a guide to create a rig speeds up the process of building skeletons.


1. Start by loading the model you want to rig.


2. Get the Biped Guide (Animate > Create > Character> Biped Guide).








3. Translate the cubes to best fit the skeleton into the model.

4. Duplicate the spine cube (at least 3 or more times) to create a tail. (Or create the tail or other additional bones after you've generated the rig from the guide).





5. Select the guide and generate the rig from the guide (Animate > Create > Character > Rig from Biped Guide. Choose Quaternion for the spine, but skeleton for the neck. I find that non-symmetrical manipulation of arms works better (i.e. both arms have positive scaling).

6. Add bones as necessary. I use 3 bone arms (the extra bone works as the elbow). I also use an upper jaw bone, that makes enveloping the head a bit easy and is a good holder (parent) for the eye and eyebrow nulls.



There are a few things to avoid when transforming the guide:

• Don't move the ribcage start cube in front of the rib cage end cube;
• Don't delete bones in the guide, wait until after you've created the rig and then delete them in rig;

modeling a character from a sphere

How to make a character from a sphere:


1. Get a polygonal sphere and increase the subdivisions to 12, 12

2. Translate components (points, edges or polygons) to give it an egg like shape

3. Select the top polygons and delete them

4. Freeze the sphere and duplicate it to make the head




5. Rotate, translate and scale the duplicate above the body

6. Select the bottom row of points and scale them so the neck part of the head matches the neck part of the body.








7. Select both the head and the body and choose, Create > polymesh > blend, to merge the head and the body into one object, > toggle off blend, this will merge the points along the neck seam.


8. Select the polymsh and freeze modeling, you might want to rename the object to something more intuitiven than polymsh.



Add the legs, feet, arms, snout, ears

9. Select polygons on the bottom of the body where the body parts will be attached.

10. Extrude along axis, increase the length and the subdivisions to make the body parts.

11. Transform the components as necessary (i.e. translate, scale and rotate, points, edges or polygons to better shape the body parts).

Add the tail

12. Draw a curve in the shape of the tail

13. Select polygons on the body where the tail will extend from

14. Extrude along curve, pick the curve, increase the subdivisions, decrease the scale per subdivision, toggle on AutoRotate




Add the eyes, nose and stripes

15. Select the polygons where the eyes, nose and stripes will appear and extrude them. In these cases the length will be very small.

16. Select the edges along the border of the eyes, nose and stripes and choose Modify > Component > Set Edge Crease Value, increase the value. This makes the nose, eyes or stripe look more like a blob of plasticine added to the model.


Colour the eyes, nose, stripes and paws

17. Select the polygons that make up the eyes, nose, stripes and paws and create clusters from them.

18. Select the clusters and apply materials to them.

19. Use the + key to increase the subdivisions.









20. Switch to shaded view to double check the result.

re-applying fcurve action tip

I had stored the tiger's animation for the first sequence into an action. I needed to tweak it a bit (see that the tiger's right foot is going through the floor), so I reapplied it using Actions > Apply > Action. But doing so, overwrote the following animation (sequence 2 and 3).

Today I was happy to discover that Actions > Apply > Paste Action ... allows me to paste the action from sequence 1 back onto the tiger and the animation from sequence 2 and 3 remain in tact (setting the target to the same model as the source).

The only caveat will be to be careful when storing the tweaked animation for sequence 1, not to remove the animation via the store command, since doing so will remove all the animation (not just between the start and end frames of the store action command).

another tip on adding deformers to an enveloped character

I've often forgotten to add the deformers to the envelope before trying to reassign points, so I thought it would be good to add this tip to the blog (it was posted on the xsi discussion list recently):

"If you want to add some more influences to an envelope, just select the
geometry, then click the set envelope button again.  The local re-assign
button only works for assigning a point to objects already set as
influences.

-Noodles"

Remember not to toggle on "Automatically Reassign Envelope", if you've adjusted the weighting of the points for the rest of the envelope.