Coord System Question

Coord System Question

I am not sure if I am doing this correctly and I am totally unsure as to why exactly. I have read the Help. I have read about this action in different threads.
Not sure why all three actions are taken.
Would someone if they have time please enlighten me?
Thanks
Move the object and resize:
then
1 Burn transform
2 Center pivot point
3 Burn pivot point

Hi uncle808us
I'm not sure what you are specifically asking about.
I'm not sure what is happening when one uses the coord system.
I hope someone answers your question because I could use a little more
enlightenment abut the coord system myself.

My Best
Jeanny

Yes I think that is the most common series of steps using the Coordinate system.

The Burn Transform doesn't have any effect on a parametric object. The size for those can be changed either in the field specific settings (which I recommend) OR by scaling the object.

1.) Burn Transform ->
Resets Scale to 1:1, also for some reason changes the Origin from Local to Global Center

2.) Center Pivot ->
Changes Global Center back to Local Center of an Object (this undoes what was just done by Burn Transform as far as resetting Origin). Leaves scale at 1:1 though.

3.) Burn Pivot ->
Changes Local Position (0,0,0) to Global Position (x,y,z)

I'm not sure if this helps you or not? If you have a specific problem, maybe I can help better. There are different situations that would call for not following this sequence exactly. For instance, sometimes I don't click the Burn Pivot as I want the position to remain at (0,0,0) rather than a Global Position.

Edit:
I should also add that if you want to just change the scale of the object to 1:1 without resetting the position, you should use the Burn Shear/Scale button instead.

Burn transform essentially matches a mesh's coordinate system to its parent's coordinate system (or the global coordinate system if it has no parent), which makes its behavior (of changing the pivot to match the parent's pivot) make sense.

Burn shear/scale matches the shear/scale to the parent's without changing the pivot.

Reset shear — not quite sure what it does because I never use it; I tend to avoid getting any shear in my meshes in the first place (which you do by avoiding non-uniform scaling of objects); presumably it changes your axes around while keeping the mesh points fixed or somesuch.

The pivot tools move the pivot around without changing scale and shear. (The center pivot is pretty weird — it places the pivot at the center of the rectangular-prism-hull of the points in the mesh (including stray points you aren't using any more).) Before using it you should probably optimize the mesh.

Swizl said:

Yes I think that is the most common series of steps using the Coordinate system.

The Burn Transform doesn't have any effect on a parametric object. The size for those can be changed either in the field specific settings (which I recommend) OR by scaling the object.

1.) Burn Transform ->
Resets Scale to 1:1, also for some reason changes the Origin from Local to Global Center

2.) Center Pivot ->
Changes Global Center back to Local Center of an Object (this undoes what was just done by Burn Transform as far as resetting Origin). Leaves scale at 1:1 though.

3.) Burn Pivot ->
Changes Local Position (0,0,0) to Global Position (x,y,z)

I'm not sure if this helps you or not? If you have a specific problem, maybe I can help better. There are different situations that would call for not following this sequence exactly. For instance, sometimes I don't click the Burn Pivot as I want the position to remain at (0,0,0) rather than a Global Position.

Edit:
I should also add that if you want to just change the scale of the object to 1:1 without resetting the position, you should use the Burn Shear/Scale button instead.

Click to expand...

Thanks for the great answers.
At the very root of my question is why is any of this done?
I was just wondering why these actions are taken.
For instance, sometimes I don't click the Burn Pivot as I want the position to remain at (0,0,0) rather than a Global Position.
In this case what would your reasoning be?

uncle808us said:

Thanks for the great answers.
At the very root of my question is why is any of this done?
I was just wondering why these actions are taken.
For instance, sometimes I don't click the Burn Pivot as I want the position to remain at (0,0,0) rather than a Global Position.
In this case what would your reasoning be?

Click to expand...

Most of the stuff I'm modeling for work is related to signs. So typically there is some element of symmetry involved. My main reason for not burning the pivot and wanting the pivot to remain at Global center (0,0,0) is to make it easier to do the math to move parts of the sign around for animation (typically the left and right frame extrusions). Since we can't do simple math equations in the entry fields in C3d (yet) that a lot of vector apps support, it's just easier to do the math that way. If I move the left frame a certain amount, I want to be sure to move the one on the right exactly the same distance. It's kind of a work around to move something a certain distance without using a calculator.

Here's an attached basic animation I made to illustrate what I'm talking about. This is not only useful to me for animation, but also if I want change the size of the sign, it's much easier to do the math. I was going to do some screen shots or make a movie, but this will be a little easier file size wise. Hopefully this explains it some.

P.S.
The best way to view this is to change the key frames to 1 per second. Go into the Animation Layout and then select the left end cap in the object browser. Notice the X Position is set to 0 for that one. Now jump to the 1 second frame marker. It moves to -2 inches. Then select the right end cap. It also starts at X Position of 0. Then will jump to 2. This is essentially what I'm doing while modeling these. I can move these in any direction based off of a 0 coordinate.

@Swizl: Thanks the animation explained it very well. I understand, I thought maybe the burn pivot point had something to do with exporting into another software.(Poser etc) but I don't think it matters so I will continue to just use.
1 Burn transform
2 center pivot point.
And not bother with
3 Burn Pivot.
Again thank you for you time and the file.

uncle808us said:

At the very root of my question is why is any of this done?

Click to expand...

Did you see my earlier reply?

Each command manipulates the coordinate system of an editable mesh in specific ways, and each is useful for _exactly_ that reason. The location of the pivot affects virtually all modifiers and creators; rotation and scale affects everything, together they create skew which is very seldom helpful, and all of these factors impact animation in different ways.

E.g. Imagine you want to tweak the pivot point of an object in a hierarchy that's in an animation; it might have non-uniform scaling (e.g. for squash-and-stretch); you can change the pivot without screwing up the animation.

It's impossible to get more specific than this. What's a screwdriver for? Tightening and loosening screws. But why would you use a screwdriver? Um, to tighten and loosen screws…

Thanks for the explanations and the jas file. They helped me at lot.

My Best
Jeanny

podperson said:

Did you see my earlier reply?

Each command manipulates the coordinate system of an editable mesh in specific ways, and each is useful for _exactly_ that reason. The location of the pivot affects virtually all modifiers and creators; rotation and scale affects everything, together they create skew which is very seldom helpful, and all of these factors impact animation in different ways.

E.g. Imagine you want to tweak the pivot point of an object in a hierarchy that's in an animation; it might have non-uniform scaling (e.g. for squash-and-stretch); you can change the pivot without screwing up the animation.

It's impossible to get more specific than this. What's a screwdriver for? Tightening and loosening screws. But why would you use a screwdriver? Um, to tighten and loosen screws…

Click to expand...

Sorry for being so dense, Yes I did read what you have written. Thank you, by the way I do know why I use a screwdriver...

@uncle @jeanny you're welcome.

Sometimes the coordinate system is a little confusing. I occasionally use pivot mode and raster snapping. This is especially true when editing the coordinates of a folder/group since some of the coordinates tools don't work on those.

Hey Uncle,

Now that it has been thoroughly described WHAT these Coord functions do, I will simply share practical applications of WHERE someone can use them.

1. Burn Transform.

• Probably the most obvious, if I have adjusted the Scale on an object in any way, and THEN I wish to add any Modifier to that object, the Modifier will actually by distorted as I apply it to the object. If you like the distortion, great, BUT if the distortion is now making things wonky, THEN delete the modifier - Burn Transform - add the modifier back and now there will no longer be any distortion.:smile:

2. Center Pivot Point

• If you start with a Box and model with Extrusions and whatever, at the end your Pivot is where it began - Centering the pivot fixes that.
• If you use an Array Modifier - the object builds out in one direction leaving your Pivot to one side - Center it.
• If you manually merge more than one mesh (Inherit Children), the pivot is defined by the parent - Center fixes that too.
• Maybe you manually Burned the pivot somewhere else and you wish to restore it - Center it.
• Maybe you have a 3rd party mesh - a car let's say, but it's combined as one object and you want to use the rims or Steering wheel for another project. As you use various selections and Split to create a new object, that object will have the pivot of the parent. Which can be troublesome when it comes time to use it in your new project. Center will make that a breeze.:smile:

3. Burn Pivot Point

• Let's say I've made a few furniture objects and I want to combine them into a new scene. Placing objects onto a floor can be tricky with Centered Pivots. Select an object, go into polygon mode, double click the center of the pivot to make it blue, then select a polygon or edge that would touch the floor, the pivot should go there. THEN Burn Pivot. Now if you set the Y-coordinate of the object to "0.0" then it is automatically at the same plane as your floor and is ready to be placed. This is also great if you have several furniture objects but they are not all sized correctly to match. By Burning the pivot to the bottom of the object, when you adjust the scale for them to all match, they scale up and down from the plane of the floor and not outward like a sphere (I hope I explained that clearly).
• Maybe you have created a door and you wish to animate it opening - OR - you've modeled a box with a hinged lid and you want the freedom to easily use rotate to open and close the box. Using the above steps to set your pivot to a hinged edge and then Burn it makes these animations and adjustments a breeze.:smile:

There are so many more instances of WHEN you might choose to use one of these Coord functions - but hopefully these scenarios will help you get the practical use for them in your project - Cheers:icon_thumbup:

Images to Renee´s comments:

1 Burn Transform / example 1
* The tube in the rear has been modified by stetting the height to 2.
* Applying a bend modifier works as expected and generates a clean 90° bend.
* The tube in the front has been modified by setting the scale to 2.
* Note that the cage of the applied bend modifier is equally scaled. Whist there is a 90° bend, the dimensions on the Y-axis are distorted as per the scale parameter.
* If that is what you want, OK. If not, burn transform (= resets the scale to 1) and apply the modifier then. Bingo, no more distortion of the circular cross-section of the pipe.

2 Center Pivot Point / example 3
* When you merge objects via the import children command, the pivot of the combined object remains at the centre of the original parental node.
* In the sample I have a dumbbell with the lower ball having been the parental node and therefore the pivot is located at 0;0;0.
* If that is what you want, OK. If not, use center pivot point to relocate the pivot for the combined object.

3 Burn Pivot Point / example 4
* The pivot for the 1/2 ring of columns is located at the middle of the height of the objects.
* If that is what you want, OK. If not, move the pivot (e.g. to the base) and use burn pivot point.

Rene66 said:

Hey Uncle,

hopefully these scenarios will help you get the practical use for them in your project - Cheers:icon_thumbup:

Click to expand...

Very clear and very helpful. Now I know which end of the screwdriver to use. :smile:

@Helmut:"Images to Renee´s comments:"
Thanks for going to the trouble of illustrating the concepts.
very helpful.

uncle808us said:

At the very root of my question is why is any of this done?

Click to expand...

If you make game models that also have a physics (collision surface) model, you need to burn the transforms before importing the two models into the game engine, otherwise the physics model may be at a completely different position than the object inside the engine.

Sometimes the models also needs to be rotated to a certain position before importing into the game engine, and the rotation needs to be burned to become the new 0,0,0 rotation.

Moving the pivot point is typically done when you want the model to rotate around the axis of a certain point / plane in the model. It could be a simple thing as a door, but also part of complex machinery.

I'd like to thank everyone who replied I now understand the uses of the coord system. Once again thanks to all.