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Kinematics
09-18-2007, 07:27 AM
Understanding the way the pivot point system works.

Hey guys, I've been using Maya for afew years now but since the move to the new company. They use a lot of cinema4d.

What I can wrap my head around is how the pivot point of objects differ between Maya and Cinema4d. Apparently, there is no freeze transformations in cinema4D (excluding plugins). This makes All objects when zeroed shoot back to 0,0,0 in world space on the grid doesn't it?

So right now I did some dynamics work in maya and baked the simulation. I exported it all into Cinema4d using the FBX format which worked great. What I figured was to start each object in maya and regardless where I move them in 3D space before dynamics. I do not zero the transformations.

When I do this. When it is brought over to Cinema4D... all goes well and the objects are in the correct positions through the animation.

The issue now is. I wish to reposition the end location after all the dynamics has taken place of all the objects. So i figured - simple. Like maya, I shall grp the object that has the animation and move the parent. thus reposition the start point of the animation.

To my surprise. It didnt work. Instead it somehow offsets itself. I am assuming cinema4d is trying to move the null objects pivot point to zero itself at 0,0,0 in world space. Why does it do that?

More importantly could someone explain to me the difference between maya and cinema4ds pivot point coordinates and how the act differently? How does cinema4d not need a zeroing of the coordinates? Why is there a world and relative coordinates point and how does it work?

I know it seems a little lazy and you think maybe I am not reading the help files. But I have, Ive also bought the cinema4D 10 Workshop book by Arndt Von Koenigsmarck (good read =) ) I guess I just need someone who has exp with both apps to tell me how they differ cause my mind seems to be stuck in the maya way.

Thanks so much guys
Sneaker
09-18-2007, 07:39 AM
Hi,
is it possible to upload a small sample?

In general it should work like you explained it.
>I wish to reposition the end location after all the dynamics has taken place of all the objects

Group all under a null have the null at 0,0,0 and make a keyframe just before you want to
reposition. Some frames later move the null object (in object mode "menu/tools/object") where you want to have it and keyframe it again.

The null should move the whole group.

-Michael
LucentDreams
09-18-2007, 02:57 PM
The reason cinema doesn't have the Zero transforms functions is simply because cinema doesn't have dual transforms on objects. In maya there are two transforms on every object, when you use the zero transform what it does is stored the actual local coordinates int he second transform, and the main transforms act as an offset of those values. Cinema sadly still can't do this.

how to get around it? well you can group a single object which creates a null at the same location as the object, then child that object to the null. this way the objects local coordinates are 0,0,0, but it isn't at the world center. however you will have to make sure that null stays put, one way to do this is a protection tag.

If your only concern is being able to get an object back to its original place, Cactus Dan has a really cool xpresso setup that he shows in his bull riding tutorial to make a home key for every object.


Its a nuissance for sure speaking as a person who uses maya and cinema, but overall it isn't as detrimental as some maya TD's make it out to be. If its causing a lot of problems, Cactus Dan's joints system does have two transforms
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