Tuesday, December 26, 2006

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.

Sunday, December 03, 2006

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.

Thursday, November 23, 2006

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!

Tuesday, September 19, 2006

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.

my smoking moose film teaser

Friday, August 18, 2006

Painting is easy ...

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

Edgar Degas

Sunday, May 14, 2006

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.

Sunday, April 23, 2006

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.

Sunday, March 19, 2006

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!

Sunday, March 12, 2006


... 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.

Sunday, March 05, 2006

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.

Monday, February 27, 2006


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.