A 3ds Max animation that can be distored to be projected on a hemisphere?

[Anonymous]

Hi,

I am very new to 3ds Max, and was hoping someone could answer some questions for me.

To frame my questions, it might be helpful to hear the end goal. I am trying to generate a striped pattern on a sphere that can rotate about its z-axis.

I then want to take that animation. Save it. Exit the program. And then be able to play it, project it through a standard projector, and have it perfectly map onto a hemisphere shaped screen.

I am able to generate a striped a sphere that can rotate about its z-axis. However, I am not sure the next steps that I would need to do to reach my ultimate goal.

Would it be possible to basically distort the sphere into some 2d planar animation that could then be saved and then played through any standard projector and have it show up correctly on a hemisphere?

Alternatively, can I start by creating a 2D planar shape that can be animated, saved, and played in a different program that would appropriately project onto a hemisphere?

Just to be clear, I am not talking about mapping the projection onto a different hemispherical object in the 3ds. I need to do this using a real projector and a physical hemisphere sitting in my house. -- I felt like that could be confusing since I can't seem to find the correct tutorial for anything like this.

Thanks for any help and advice that could be offered. I really appreciate it.

[leeminardi]

Could you post a couple of pictures showing what the stripes would look like on the hemisphere?

Since the projector will be a finite distance from the hemisphere it would not be able to create an image at the extreme edges.

Here's a plane with a checkered cutout map and a target light projecting onto a hemisphere.  I assume you are asking how to determine the design of the cutout map that would yield the desired stripe pattern on the hemisphere.

[Anonymous]

Hi Lee,

I really appreciate the response. I might not have been very clear in my original description at what I am trying to accomplish. I hope the attached photos will make it more obvious.

The screen shot show the sphere and stripe pattern that I have created. Essentially, I have animated this sphere to spin around its z-axis. I basically want to take this animation, save it to my computer, and then use a vga/hdmi connector to my computer to transfer my screen to a projector and then use the projector to project this image on actual hemisphere sitting in the room right next to me.

I guess what I have done is create the output I am hoping for, but I don't think what I did actually translates well to what I actual want to accomplish -- which is a bunch of stripes moving around an axis of a hemisphere similar to what I have produced in the animation i made in 3ds max.

Side question -- the bottom left aspect of my sphere is shaded darker. Is it possible to remove that shading?

Thanks again for taking time out of your day to help. I really appreciate that.

Best,

Brett

[Anonymous]

[leeminardi]

Hi Brett,

It sounds like what you want to do is project an animated image onto a stationary hemisphere that yields an image that makes it looks like it is spinning like in your avi file.  Yes?

What effect do you get when you project the animation you posted?  I assume that the longitudinal edges of the stripes will remain geodesics (great circles) but I am trying to visualize how they should change as they spin away from the viewer as a result of being projected onto a sphere instead of a plane.  My guess is that the spacing should increase to compensate for the increased foreshortening cause by the sphere.  A sketch and a little trig may help you out.

As for your question "...the bottom left aspect of my sphere is shaded darker..." you could use multiple lights symmetrically positioned or a single light directly inline with the center of the sphere and the viewing point (camera).  Note that removing all shading will reduce the effect that you are looking at a sphere. 

Lee

[darawork]

I would render out at 6k x 3k and use two projectors at least. My friend, a Techno musician with a Masters in Electronic Music (Trinity College Dublin) used eight projectors for his final year Thesis. It was amazing.

[darawork]

Why not rent a dome? Most 3DSMax render engines support 360 rendering. Which are you using? Sorry, I skimmed.

[Anonymous]

Hi Everyone,

Thanks again for taking time to help me with the problem. Here is an example of what it looks like when I project the animation on a sphere.

Any advice on where to go to from here?

Best,

Brett

[Anonymous]

I am using 3ds Max 2018, and used whatever the default rendering engine. Can you produce a 360 render of an animation, and would that help this problem?

best,

Brett

[leeminardi]

One method to animate the progression of a stripe around a hemisphere would be to create a shape that casts a shadow onto the hemisphere and as it moves it changes shape to yield the shape of the shadow you want.  For example, in the image below I created a closed spline and added an extrude modifier to fill it in (red shape).  I then manipulated its end points and midpoints to yield a stripe centered on the sphere.  I made a copy of the shape and moved it to one side and manipulated its vertices to yield a projected shadow close to what I thought was needed.  This exercise gave me a feel for how the shape must change as the shadow stripe moves around the sphere.

Here is the resulting rendering.

As you can see in the rendered image the off center stripe is not quite right.  To get a better shadow shape it might take additional vertices along the edges.

To create the full animation you would need to  have the shape change as it moves across the hemisphere.  This might be able to be done by morphing from a before shape to an after shape or by animating the position of the vertices.  Either way, there is a bit of work involved.

[Anonymous]

Hi,

Thank you for the continual help. I appreciate it. Would it be possible to animate the stripes moving across the hemisphere to mimic what it would look like if a sphere was rotating about its central axis?

Unfortunately, I need to it rotate.

Does anyone know how to use the physical camera feature that lets you distort the view? I tried using it, but wasn't really clear on how to work it or if there is some guide to distorting the animation to correctly fit a need.

Best,

Brett

[Diffus3d]

Hello @Anonymous!  Thanks for reaching out, I love helping people!  

I took a stab at explaining how I might try this.  I had to break it up into 2 videos, thanks for your patience!

Please let me know if you have any questions or if I missed the mark here.  I'll do what I can to help.  I also attached my scene file so you can view it.  Sorry for it being Max 2016, I'm doing a side gig that requires it at night but all the concepts are the same.  Thanks!

For some reason I cannot embed video like I used to, so here are the links.  
Also, I apologize for the background noise.  

http://autode.sk/2HGveHz
http://autode.sk/2CE5Ka7

One thing I didn't explain well after rewatching my videos are why an offset of 1.5 is equal to 540 degrees.  If the UV square is 1:1 then a full tiling or revolution is equal to 1.  (Imagine panning a tiling texture from left to right, once it hits the end it starts again.)  So an offset of 1.5 is 360 degrees plus another 180 degrees, which is 540.  This may not make sense until you view the video.  Thanks!  

Best Regards,

Alfred

[Diffus3d]

I got a PM from a user asking why bake it instead of just rendering from top down.  I suppose you could do that, but the camera has a FOV which could distort the projection a bit whereas the baker is always perfectly flat.  I just figured it removed a potential point of failure or error from the process.  

Best Regards,

Alfred

[darawork]

My very first animation with max 4 was a spaceshuttle going through a black
and white wormhole. This thread is gold. :1st_place_medal: