MoGraph arrow head alignment problem
by John Hammond
on
Jun 25, 2009 at 7:09:57 pm
Hi,
I am making some 3d arrows with mograph.
I have a radial matrix and an Inheritance Effector assigned to an animated Null. So the matrix follows the null around. I then added the Random Effector to add some variation in the movement.
I then used Tracer to trace the paths, and Sweeped then with a rectangle.
Now I want to add the arrow heads. I made my arrow head geometry and created a Cloner, on Object mode, with the object set to my matrix that's creating the trace. So now the arrow heads are stuck to the start of my arrows.
I can't get them to align to their direction of travel.. Tried a few things on mograph and I also tried using a second Matrix Object to create thinking particles on the original matrix. I added a PAlignment node set to direction of travel, but it didn't seem to work.
Any pointers would be greatly appreciated!
Thanks,
John
Re: MoGraph arrow head alignment problem by John Hammond on Jun 26, 2009 at 1:24:38 pm
I have just test rendered my animated lines and found that they seem to render horribly, jumping about all the time. When I play in the C4D timeline it looks nice and clean... Any ideas? I've had trouble like this before with tracer, where it jumps from point to point (would need some kind of sub-frame sampling maybe).
Maybe I need to approach my 3D arrows in a different way. I could use tracer or any method to create a bunch of Splines, and then use the SweepNurb's End Growth Parameter to animate the Sweeps across the splines.
I could then attach the arrow heads with the Align to Spline Tag, again with the position parameter animated in sync with the End Growth % of the SweepNurbs. Maybe wire the two parameters together with Xpresso.
Would love to know your thoughts after you've taken a look at my scene file.
Re: MoGraph arrow head alignment problem by John Hammond on Jun 29, 2009 at 9:49:26 am
Hi,
Thanks for this, it seems to work well when I play it in the software, but as soon as I render the animation (either with or without saving) the render looks terrible with the 3D lines shooting way forwards jumping through the arrow heads.
Re: MoGraph arrow head alignment problem by Jack Evans on Jun 30, 2009 at 12:50:39 am
I can duplicate this, using the file that Brian posted above. If I render it to the picture viewer, I get spikes sticking through the arrow heads. If I do a render view, or if I render a preview, I don't get the spikes. When I render out the animation, I get the spikes with full render, hardware preview, or software preview.
FWIW, I'm still using the demo (R11.010) on a Windows Vista 32 bit computer. I wouldn't think this would be a demo-related thing, but, ya never know.
Other quirks: In stepping through the frames one at a a time, I notice right away that the circled rectangle object is poking through the arrow head object. You can see this pretty clearly around frame 9. It seems like it would look better in any event if the rectangular end of the sweep object could be made to just touch the back of the arrow head object.
Also, if you step through to, say, frame 25, then click the button to jump to the end frame, the arrowheads jump to the correct position, but the sweep object doesn't make its arc; it jumps in a straight line from it's position in frame 25 to the end. If you do a render view of this odd arrangement, it does show up in the render.
I don't know enough about C4D yet to suggest a solution, but maybe there something that can be tweaked in the sweep NURBS object.
Re: MoGraph arrow head alignment problem by Brian Jones on Jun 30, 2009 at 1:35:32 am
[Jack Evans]"I'm still using the demo (R11.010)"
I'm using 10.5 on a Mac and can't get it at all. Maybe something to do with the version...
[Jack Evans]"circled rectangle object is poking through the arrow head object"
you can get rid of that either by scaling (End Scale or Scale in the Details) the SweepNurb or by adding a little to the P.Z in the Transform tab of the Cloner Object.
[Jack Evans]"it jumps in a straight line from it's position in frame 25 to the end"
that's just normal if you jump to a frame. It can't calculate the frames in between, the spline that's being swept is the result of the Tracer inside the SweepNurb and that needs to be calculated.
Re: MoGraph arrow head alignment problem by Jack Evans on Jun 30, 2009 at 11:36:54 am
Hmm... I still can't get that poke-through fixed. Not sure what I'm doing wrong (again, complete C4D noob here) but it won't accept any changes to the P.Z value for the cloner object at any frame. I change the value, then it blinks back to what it was before. I can change the position value of the arrow head object, but that doesn't do anything; the sweep object continues to follow it. It looks like the end of the sweep object is tied to the center of the arrow head; I'm wondering if the sweep were following a null object parented to the arrow head, if it would work differently.
I'm ordering the live version this week, I'll try it again once it arrives (maybe there's a patch that covers it that didn't make it into the demo). Since the problem is reproducible and the scene file here is pretty basic, I would think it wouldn't be too hard for the engineers to track down if someone sends in a bug report.
Re: MoGraph arrow head alignment problem by John Hammond on Jun 30, 2009 at 11:56:07 am
Hi Jack,
The Arrowhead's positions are firstly arranged in a radial pattern by using the Cloner Object (mograph). This cloner then flies around the circlePath through the use of the Align to Spline tag on the cloner. (animating position %).
To adjust the arrow's position you can alter the original object's pivot point, or add a plain effector to the cloner and adjust the position params.
However, I don't think this issue is related to the crazy render I am getting . . the geometry is jumping around all over the place (see render above).
Re: MoGraph arrow head alignment problem by Jack Cook on Jun 30, 2009 at 12:13:28 pm
John, I don't know if this is exactly what you're looking for, but here's a tutorial about how to make an object follow the growth of a sweepNurbs object. I've used this to make an arrow grow in a similar way to what happens in your file.
Re: MoGraph arrow head alignment problem by John Hammond on Jun 30, 2009 at 12:43:32 pm
Cool, thanks JAck. I've use Xpresso a little like this tuts first example.. But this tut goes deeper with the vector2matrix and matrix to HPB.. I need to work through that and try to understand it!
