Page 2 of 3

Re: Switching Cam Position Based on Distance to Targeted Object

Posted: 16 Nov 2011, 14:02
by Frank1000
ya gotit, edit instead of explode is the key. I made a new ICE tree and now everything is working good, thx for showing how. I was curious to follow your node logic, but must confess, although I'm quite 3D savvy in XSI, this is really new to me. I understand the concept of scripts, represented by nodes, that can be tied together and their variables and functions can be edited, but oh boy, this takes a while before getting fluent with it.
I wanted to make a distance animation, that in this case starts behind the car, and then moves in front of the car during the course of action, but got stuck at the behind-checkbox. Checking if the distance needs to be a value from negative to positive, while zero is the closest, negative is behind and positive is in-front.
Basically the goal is, now that the scene works good, to create the view- templates (let me call it so) to define view sequences.
Meaning a compound of multiple view-elements of how the object is finally seen: e.g.
1st-element 10sec.: distance animation from behind to in front;
2nd-element 5sec: stay in front of the object;
3rd-element 2 sec: jump to a fixed-watching-position and watching the object from there;
4th-element 6sec: leaving the fixed-watching-position and make animation towards a certain distance again ...

something like that, and combine it into a template, so I can make the different viewing templates and start call them up manually from something like a control-panel during the animation runs. Connecting the templates to number keys on the keyboard for example.

Image

Re: Switching Cam Position Based on Distance to Targeted Object

Posted: 18 Nov 2011, 01:41
by Frank1000
Hi Chris, I’ve watched myself into a lot of the ICE movies now and it’s becoming quite clear to me now how ICE works and how it’s handled.
If you exactly know what you need to achieve and are not just using ready templates, it basically is understanding the algorithm and math of the needed function and to bring it into the language softimage uses here ... don’t know if that is one of the major ones c++ or so, or an own one.
ICE is the GUI to it and comes with a management and a load of “includes” or “snippets” or as it’s called in ICE with “tasks” and “tools”, some lighter, some heavier. So it basically is a gate to the 3D / programming universe.

I went back and built a 1unit to 1meter model, so don’t have to translate some real world values.

Next step for me is to determine the average speed that is being driven (by the cars) at the corresponding speed track location.
In terms of car weight, slipping, acceleration factor (power), deceleration, max. speed, car weight, centrifugal force, and maybe some more ... doesn’t have to be all the way finite elements here, just a few values, so I can determine some useful average speed at the respective location.
That allows me to mathematically determine how close I need to place camera nulls, so the resulting movie stays smooth, and place the nulls automatically.

I thought the best is to start out with a centrifugal force that, in conjunction with the path ahead determines which max. speed can be driven by the car, so the car then accelerates and decelerates accordingly to be as fast as possible but at the same time to stay on the track.

I checked myself through the ICE tasks and tools but wasn’t able to find something centrifugal power or so ... any idea if there is a tool already available ? If no centrifugal force there yet I guess I have to dig 1 level deeper and check how to make one.

Re: Switching Cam Position Based on Distance to Targeted Object

Posted: 18 Nov 2011, 02:00
by Frank1000
oh found it, syflex.gravity

Re: Switching Cam Position Based on Distance to Targeted Object

Posted: 18 Nov 2011, 11:56
by Chris_TC
Frank1000 wrote:In terms of car weight, slipping, acceleration factor (power), deceleration, max. speed, car weight, centrifugal force, and maybe some more ... doesn’t have to be all the way finite elements here, just a few values, so I can determine some useful average speed at the respective location.
There is a lot of documentation out there on these things. If you search Google for "game car physics" or similar you will find many results because these types of algorithms are used all the time in game programming.
A good series of articles is this one, Physics of Racing by Brian Beckman:
http://phors.locost7.info/contents.htm

I had started working on an ICE car simulator of sorts, but never got around to letting the car make turns because the formulas started to confuse me a bit:
http://vimeo.com/28309792
That allows me to mathematically determine how close I need to place camera nulls, so the resulting movie stays smooth, and place the nulls automatically.
If you want the camera to smoothly follow the car, I think it would be preferrable to use some kind of pose constraining or parenting (either regular or through ICE) than to let the camera jump from null to null.

Re: Switching Cam Position Based on Distance to Targeted Object

Posted: 18 Nov 2011, 15:03
by Frank1000
great resources ! I'm wondering if someone ever built a working auto race ICE compound already.