Comments on: Splinophilia By Victor Navone (IPO Curves)

By: Sandy

Sandy — Fri, 13 Jul 2007 02:28:03 +0000

Your tutorial is good,
I am looking for some help to learn the Ipo Curve editor and its uses regarding the Blender.
I am finding any help hardly about that.
Could you please help me out.

By: malefico

malefico — Sat, 02 Jun 2007 15:28:03 +0000

One of the biggest problems about using IPO editor for character animation, is that unlike the Spline Editor shown in Navone's tutorial, Blender's uses Quaternions in the interface. This problem was already discussed in the funboard list. More tools to switch among Euler/Quaternions should be added before you can really concentrate in working with IPOs for character animation.

Regards

By: nemyax

nemyax — Sat, 02 Jun 2007 08:33:07 +0000

> Blender's animation splines are THE NICEST i have ever used.
You might change your mind if you spend some time in Maya's or Houdini's graph editor. The sorting and filtering options, per-key interpolation functions, choice of Eulers/quaternions for rotations etc. make one really feel the difference.

By: Tim

Tim — Sat, 02 Jun 2007 05:56:50 +0000

Sovereignncc-e,

Thank you for clarifying that, your explanation made it easier for me to understand and you are so right about learning with Blender. I was able to help my 12 year old daughter to understand her math, volume, unwrapping solids, X & Yplotting etc. It made it much easier for her to visualize the concepts. using Blender.

By: Sovereignncc-e

Sovereignncc-e — Sat, 02 Jun 2007 01:43:13 +0000

I am a math major, and I can confirm that the coordinate system in the picture is definitely a left-handed coordinate system. To determine whether or not the coordinate system is right or left-handed, point your right hand in the direction of the x+ axis, and curl your fingers in the y+ direction. If your thumb points in the z+ direction, the coordinate system is right-handed. Otherwise, it is left-handed.
Also as a math major, my knowledge about Blender made a lot of mathematical principles a lot more fun to learn about. The IPO editor corrisponds very nicely to parametric graphing. Additionally, the slope of any of the curves is the speed of the object, which comes straight from differential calculus. I also believe that it is a lot easier for me to visualize 3D objects due to my proficicency in Blender. Blender is a great example of an application for math.

By: Tim

Tim — Fri, 01 Jun 2007 20:50:53 +0000

LayBack,

Hmmm, I'll leave up the definition to the mathematicians and engineers. The main point I wanted to convey is that up is Z in Blender and in Maya, which Victor is using, Y is up.

Perhaps for future articles with these types of technical details, I could use you as a source to verify that my information is correct.

Again, Thanks for clarifying it.

By: LayBack

LayBack — Fri, 01 Jun 2007 20:28:12 +0000

Hi Tim,

I have to correct myself. I just read about POVray having a left handed coordinate system …

Please (re)read http://en.wikipedia.org/wiki/Right-hand_rule Right-handed-ness is not about pointing "up" or some where else. It is about the relation of the three axes to one another. You could even have X pointing "up" and still have a right-handed system. Read the article above and try the rule as shown in the picture there.

By: Tim Formica [Room335]

Tim Formica [Room335] — Fri, 01 Jun 2007 19:13:04 +0000

LayBack,

The XYZ JPG, it a rotated screen shot of Blender, split between front and side view where X & Y are on the horizontal plane, X is positive to the right and Z points up, making it right handed.

Also, I didn't realize that about the other applications. So I've edited the article.

Thanks for spotting that.

By: LayBack

LayBack — Fri, 01 Jun 2007 18:40:49 +0000

Hi Tim,

I didn't notice first but your coordinate system (xyz-2.jpg) is LEFT handed. It becomes right handed if you switch the direction of _one_ of the axes.

By: LayBack

LayBack — Fri, 01 Jun 2007 18:35:26 +0000

Hi Tim,

there is a typo in the header. It should be 'Curves' instead of 'Cruves'.

A bit off topic:
As for 3DS Max and Maya: both use right handed coordinates (look at some screenshots). In Blender and Max Z points up and Y points away from the front view. Mayas coordinates are rotated 90 degrees around X so that Y points up and Z points straight in your face (in front view). But all are right handed and I know of no application (3D or CAD) that uses a left handed system (and I used some, I am an engineer).