I just purchased Bongo, and I am having a hard time getting Bongo to move the camera from a typical perspective view to a perspective view that is directly overhead without some weird behavior in the camera rotationally “twitching”. See attached video. Any help getting a smooth transition would be greatly appreciated. Its really the main reason I purchased this software and it would be great to get it to perform. Any help is greatly appreciated.
Here is a link to an illustration of the issue.
Without having the model, it’s just guess work… but I’m going to guess that it’s what we call the z-up problem. When the camera goes over the z-axis (or is parallel to) it doesn’t know which way is up and down and therefore flips.
The solution is to move the animation away from the 0 point and then the camera shouldn’t be confused about the axis anymore.
Hi Mike,
In my opinion it is more comfortable to use the Simple Constraints for view animation.
Although the z-up problem can also cause problems there 
Luc
Thanks so much for that demonstration of the camera-to-path functionality. I’m definitely going to use that for my next pass. Love the way one can apparently edit the line. So much smoother that way. I’m still not clear if what I’m attempting to do is somehow not allowed in Bongo. Would love it if there there was a way to make the camera constrained to “y-back” instead of “z-up” as I approached directly overhead. This is for an architectural presentation and it’s important to be able to generate a plan view.
Yeah, what you are describing totally makes sense. It’s the Z-up problem. I’m not clear if what I’m attempting to do is somehow not possible in Bongo or if there is a viable methodology to accomplish it. Unless I’m fooling myself, the link you shared makes it sound plausible. I would love it if there there was a way to make the camera constrained to “y-back” instead of “z-up” as I approached directly overhead. This is for an architectural presentation and it’s important to be able to generate a plan view.
This “plan view” would it be parallel projection or perspective? I don’t think there is a way to switch between different projection types during an animation!
It is still a perspective view, even though it is view straight down.
Hi Marika.
Thanks for your help.
Attached is the file I am working on. Not much too it, but hopefully it will help illustrate my challenge. I’m also attaching a screenshot showing the two views I want to travel between along with a couple screenshots that hopefully give an idea of the basic animation. I thought it seemed simple enough, but appearances can be deceiving :). Thank you for any help you can spare. I went ahead and tried Luc’s camera as path approach. I really like this workflow but I’m still getting the camera spin at the top. I’ve tried messing with the bongo pivot points a bit but I feel like I might be creating a mess without more experience. Any help is appreciated.
Sample for Bongo Forum.3dm (152.5 KB)
Here is another video showing my limited progress and simplifying my problem (and hopefully the solution). Am I asking Bongo to do something it can’t do? I’m spending a lot of time on this problem and would really appreciate anyone who can tell me how to solve it if it is not impossible. If it is impossible it would be helpful to know that as well.
Test File For Simple Overhead Rotation.3dm (129.3 KB)
In order for the object to not appear upside down at the opposite end of that arc the view also needs to rotate around the direction it’s looking while its moving along the path. Something like this:
Because of how Rhinos views work keeping a consistent up/down left/right while animating is tricky. Bongo should obviously do better here. My recommendation would be to adjust your camera path slightly so it doesn’t follow that perfect arc. I think the result might be closer to what you’re after. Adding some extra keyframes around the middle of the portion of the animation may help things feel less jerky.
AlternateCameraPath.3dm (27.4 KB)
Thank you for the reply Joshua. You might check out my earlier post to this thread featuring four still images showing what I am going for. I don’t want to change the orientation of the camera as it goes over the top of the cube at all. Any thoughts on how to do this?
From a human perspective, there’s something logical about the viewport’s inversion in Rhino. Left out, the viewer ends up upside down.
I managed to achieve the above video by using the Y-axis as a vertical dimension, thus by placing the base of the pyramid vertically. A camera rotation of -90° in the Perspective View gives the illusion of the pyramid being upright. Setting the CP ‘World Front’ completes the hocus-pocus. Hocus-pucus.3dm (71.0 KB)
With this trick, and appropriate rotation of the view via keyframes, I think I’ve managed (more or less) to approache your goal. The curves for the camera point and target are the result of some patient tweaking!
Mike hocus-pocus.3dm (69.5 KB)
Luc
Hi Luc. Thanks so much for your efforts. You have indeed solved my problem. Thank you. I thought about playing around with the axis but ultimately wound up going another route using the set view plugin, in Grasshopper which ultimately negated the need for Bongo altogether. Still, I do think I’ll have future animation needs that are less about manipulating the view and more about the movement of connected folded plates. I’m hoping Bongo will do a better job with that kind of manipulation and the purchase will have proved useful. Thank you for taking the time to help. Without vetting the state of my last save, I’m attaching the last grasshopper file I used that did address all the issues the built on that first initial challenge I had with views. I believe most of the relevant geometry is internalized.
Folded Plywood Video Work V2.gh (79.4 KB)
