A rotation is not a matrix, it is a vector [which represents the rotation axis] and a angle [expressed in degrees or radians representing the amount of rotation around the axis].iamVFX wrote:wow, I didn't even know that rotation is matrix and can provide local transforms. that's cool, thanks!dwigfor wrote:Part 3 is now online: Parenting_Position
(Introducing "Multiply Vector by Matrix")
TUTORIAL: Intro to ICE Kinematics
- TwinSnakes007
- Posts: 316
- Joined: 06 Jun 2011, 16:00
Re: TUTORIAL: Intro to ICE Kinematics
Re: TUTORIAL: Intro to ICE Kinematics
you know what i mean so that it can be converted into 3x3 matrixTwinSnakes007 wrote:A rotation is not a matrix, it is a vector [which represents the rotation axis] and a angle [expressed in degrees or radians representing the amount of rotation around the axis].iamVFX wrote:wow, I didn't even know that rotation is matrix and can provide local transforms. that's cool, thanks!dwigfor wrote:Part 3 is now online: Parenting_Position
(Introducing "Multiply Vector by Matrix")
Re: TUTORIAL: Intro to ICE Kinematics
Part 4 is online: Parenting_Rotations
Important to remember: Child Rotation * Parent Rotation
Important to remember: Child Rotation * Parent Rotation
Re: TUTORIAL: Intro to ICE Kinematics
Part 5 is online: Parenting_Simplified
Important to Remember: Child Local Transform * Parent Global Transform = Child Global Transform
I forgot to mention that I had already offset the Child's position in the SRT to Matrix node back in Tutorial 2.
Important to Remember: Child Local Transform * Parent Global Transform = Child Global Transform
I forgot to mention that I had already offset the Child's position in the SRT to Matrix node back in Tutorial 2.
Re: TUTORIAL: Intro to ICE Kinematics
Rork wrote:Please stick to Vimeo.
I do understand the Google requests, but on Vimeo at least there's some organizing going on.
And you don't get retarded comments on the videos you're posting ;-)
I tried Vimeo before, but I think the files are too big. I'll see if I can recompress them, because I would like to include these with everyone else's stuff... What settings are recommended?
- xsisupport
- Posts: 713
- Joined: 09 Jun 2009, 11:02
- Location: Montreal Canada
- Contact:
Re: TUTORIAL: Intro to ICE Kinematics
I can convert them to mp4 for ya, if you're stuck.
Re: TUTORIAL: Intro to ICE Kinematics
Sorry for the confusion. I think I even made a comment like "oh I thought I needed to convert that before" while recording it... I run into the problem when multiplying the rotations together, so then I convert the matrix back to rotation. Yes, I believe rotation is a 4D vector (X, Y, Z, W). You can convert rotation into a rotational matrix by plugging "Axis and Angle to Rotation" -> "SRT to Matrix" -> "3x3 Matrix". I did intend to use "Multiply Vector by Matrix", but should have converted it to 3x3 matrix first. I'll have to look into using just a "Multiply" node as TwinSnakes007 mentioned earlier.. Never tried that...TwinSnakes007 wrote:A rotation is not a matrix, it is a vector [which represents the rotation axis] and a angle [expressed in degrees or radians representing the amount of rotation around the axis].iamVFX wrote:wow, I didn't even know that rotation is matrix and can provide local transforms. that's cool, thanks!
I've got some other tutorials that I'd like to offer, but I ran into a problem with my next one that needs sorting out.. I got some flipping issues when I was creating my Turret setup. Need to open an earlier project to see how I solved it.. I think I may have used ArcTan2 rather than Increment Rotation by 2 Vectors, so I gotta relearn that...
Thanks for watching!
-Dave
Re: TUTORIAL: Intro to ICE Kinematics
I appreciate the offer, Stephen! Do you need the source files? They're fairly large (probably 6 gig in total).xsisupport wrote:I can convert them to mp4 for ya, if you're stuck.
What resolution does everyone record their videos at?
- xsisupport
- Posts: 713
- Joined: 09 Jun 2009, 11:02
- Location: Montreal Canada
- Contact:
Re: TUTORIAL: Intro to ICE Kinematics
I have Camtasia Studio, so I would load the .avi and export it as .mp4.dwigfor wrote:I appreciate the offer, Stephen! Do you need the source files? They're fairly large (probably 6 gig in total).xsisupport wrote:I can convert them to mp4 for ya, if you're stuck.
What resolution does everyone record their videos at?
Or could you just download the .flv from youtube and use that?
Re: TUTORIAL: Intro to ICE Kinematics
Finally got these up on Vimeo. If someone else needs help with it, I used Adobe Media Encoder and set it to Vimeo HD. Takes a long time for Vimeo to convert it, though... Much longer than Youtube...
Re: TUTORIAL: Intro to ICE Kinematics
too hard to me, so what is the point of ICE kinematics? what that can do
Re: TUTORIAL: Intro to ICE Kinematics
Why do you need to know this? Let me try to explain a practical use of this. Since creating these tutorials, I wanted to try to create a box representing the camera's view frustum (what can be seen through the camera, with boundaries on the near/far plane. In addition I also create a projection plane from the camera, similar to this: http://julianjohnsonsblog.blogspot.com/ ... -grid.html
In order to keep that grid "parented" to the camera as the camera moves around, you need to multiply the point positions by the camera's global transform (4x4 matrix).
Get Data (self.pointposition) -> Multiply Vector By Matrix -> Set Data (self.pointposition)
camera.kine.global -^
Another example on why you should learn 4x4 matrix.. I was trying to emit points from an object's point positions. When I scaled, rotated, or moved the objects, the points would no longer emit from the object's point positions. To fix this, you need to multiply the point positions by the object's kine.global.
Or say you create a particle simulation and then want to change shape to cylinder shaped points and want to rotate them so they are on their side. Simple. Axis and Angle to Rotation (along Z 90degrees) * Get Data(self.orientation) -> Set Particle Orientation
I've found this stuff to be extremely helpful when working in ICE in general, not just ICE Kinematics. Biggest thing to remember is that the order that you multiply stuff is very important. Child * Parent.
Think about this:
1) You start walking forward 2 steps; you turn right 90 degrees
2) You turn right 90 degrees at start; you walk forward 2 steps.
Both involved walking forward 2 steps and turning 90 degrees, but they result in vastly different end locations.
Hopefully that helps.
-Dave
In order to keep that grid "parented" to the camera as the camera moves around, you need to multiply the point positions by the camera's global transform (4x4 matrix).
Get Data (self.pointposition) -> Multiply Vector By Matrix -> Set Data (self.pointposition)
camera.kine.global -^
Another example on why you should learn 4x4 matrix.. I was trying to emit points from an object's point positions. When I scaled, rotated, or moved the objects, the points would no longer emit from the object's point positions. To fix this, you need to multiply the point positions by the object's kine.global.
Or say you create a particle simulation and then want to change shape to cylinder shaped points and want to rotate them so they are on their side. Simple. Axis and Angle to Rotation (along Z 90degrees) * Get Data(self.orientation) -> Set Particle Orientation
I've found this stuff to be extremely helpful when working in ICE in general, not just ICE Kinematics. Biggest thing to remember is that the order that you multiply stuff is very important. Child * Parent.
Think about this:
1) You start walking forward 2 steps; you turn right 90 degrees
2) You turn right 90 degrees at start; you walk forward 2 steps.
Both involved walking forward 2 steps and turning 90 degrees, but they result in vastly different end locations.
Hopefully that helps.
-Dave
Re: TUTORIAL: Intro to ICE Kinematics
Thank you very much for these tutorials - they helped me a lot.
Arnold for the masses!
Re: TUTORIAL: Intro to ICE Kinematics
Super helpful, Thanks!
Re: TUTORIAL: Intro to ICE Kinematics
Thanks for these! Very helpful, and right to the point!
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