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General Category => General Anim8or Forum => Topic started by: JAYAKUMAR on April 14, 2009, 05:26:07 am

Title: morph targets for parametric shapes
Post by: JAYAKUMAR on April 14, 2009, 05:26:07 am
i have this doubt on how to make a morph target for a parametric shape.
let me be specific , i wanted to animate a spring compression and expansion sequence but it becomes tedious to move all the points of a mesh, so i wanted to know if it is possible to make a morph target for a parametric spring or atleast scale it non uniformly in the sequence page
 ???
Title: Re: morph targets for parametric shapes
Post by: floyd86 on April 14, 2009, 06:04:03 am
What you're trying to do, can easily be done using Morph targets (http://anim8or.com/manual/3_object_editor.html#morph_targets).
In object mode create a spring (http://raxx.cg-nation.com/Com/ASLTopic/spring.zip). Make a new morph target (build>morph taget>new).
Then non-uniform scale your spring and your done. In scene mode the object will have the option to turn the morph target on and off.
Title: Re: morph targets for parametric shapes
Post by: hihosilver on April 14, 2009, 05:27:34 pm
Here (http://arkavision.com/oldsite/programs.html) you can download MorphEnvy, a program that creates morph targets using 2 3d objects.  The objects must both have the same exact structure, number of points/edges/faces etc.  This allows you to create 2 separate springs (with all the same settings except perhaps stretch), then you can create a morph target using the tool, and the volume of the object will be kept and you'll have a smooth morph target.
Title: Re: morph targets for parametric shapes
Post by: JAYAKUMAR on April 15, 2009, 08:36:25 am
floyd  i tried but it doesnt work on parametric shapes as well as built in shapes like cube or cylinder , it works if i convert the shapes to mesh.
thanks hiho but i want to do it in anim8or
Title: Re: morph targets for parametric shapes
Post by: mcheccyb on April 15, 2009, 09:17:55 am
morph envy was built for anim8or.

so technically it's still using anim8or. (kinda)
Title: Re: morph targets for parametric shapes
Post by: hihosilver on April 15, 2009, 12:30:17 pm
mcheccyb is correct, it's simply a tool built to help anim8or.  You are still staying within the realm of Anim8or.  If you want to use morph targets, then yes, you will have to convert it to a mesh.
Title: Re: morph targets for parametric shapes
Post by: JAYAKUMAR on April 19, 2009, 12:09:23 am
thankx everyone
Title: Re: morph targets for parametric shapes
Post by: JAYAKUMAR on April 19, 2009, 12:11:55 am
this is for mr.steve , it will be really nice if morph targets can be created directly for parametric shapes, just a food for ur thought
Title: Re: morph targets for parametric shapes
Post by: Raxx on April 19, 2009, 01:50:35 am
That's not exactly possible (by that I mean it's not feasible). Parametric shapes are made through mathematical formulas and don't actually contain vertex information that can be utilized by morph targets. Why do you require it for parametric shapes anyway? Just convert to mesh.
Title: Re: morph targets for parametric shapes
Post by: ENSONIQ5 on April 19, 2009, 03:21:51 am
Scaling a spring mesh to create a morph target that could be used to make the spring appear to compress is not strictly accurate, in terms of the physics of a real spring.  Scaling will not only change the length of the spring, it will distort the cross section of the coiled steel as well.  If the spring was made by rotating a circular N-gon around an axis, then stretching the mesh will have the unwanted effect of making the spring appear to have been made by rotating an ellipse.

A real coil spring, when compressed or expanded, puts a torsional stress on the coiled rod, effectively twisting it across it's full length.  In some cars the suspension is based around a torsion bar, which is effectively an uncoiled spring.  To be strictly accurate, the way to create a spring compression morph in animator would be to rotate each N-gon cross section very, very slightly on an axis perpendicular to the spring long axis and the N-gon cross-section plane.  Although this would be VERY tedious, it would provide an accurate model of the way the spring expands in overall diameter when compressed, and shrinks when stretched.  Perhaps a compromise would be to shift each cross section N-gon a tiny bit in the direction of the spring's long axis, creating an overall change in length but not changing the shape of the actual coil.
Title: Re: morph targets for parametric shapes
Post by: karate5662 on April 23, 2009, 03:20:18 pm
it would be nice to tween the attirutes of a parametric shape, like the length of a spring.