Manipulating the visibility of an object with another object.

[Anonymous]

basically i want to have a large (invisible) object that i can us as a visibility mask for a smaller object so that the smaller object is only visible when it passes through the larger object. ive seen this done years ago but cant remember how.

any help is greatly appreciated 

[irishman_team_kilber]

you can add a invisible track in the dope sheet/CV editor. as long as you have animation key set http://www.3dmax-tutorials.com/Add_Visibility_Track.html

https://books.google.co.uk/books?id=clTfqWqMEIIC&pg=PA864&lpg=PA864&dq=3ds+max+invisible+track+dope+...

i cannot find the update documents where it shows you how to how to do this. the only two threads i have found is these two. maybe if you look under help references and use the search box and type in invisible into the search box it should be under adding an invisible track double click on that and will tell you how to add it.

If autodesk has not remove this feautre sorry i cannot help you anymore because i have max 9

[Anonymous]

i know how to do that. not the same thing. thnx

[irishman_team_kilber]

@Anonymous sorry if this is not the answer you wanted, that is the only way i know of add an invisible track in 3ds max.

[Alfred.DeFlaminis]

Hello @Anonymous,

I'd like to help here, but I'm not sure I fully understand the effect.  Would the object go invisible in parts?  Or as a whole once it touched the activator object?  Or is it more like Portal, where the parts that have gone through go invisible but the parts that haven't don't?  (If so, any chance they were 2 objects being sliced in the same place which gave the effect?)  Just trying to wrap my head around it.  

If you are on 2017 or later, there is a map which can blend between two maps that would be decent in an opacity or refraction slot.  It's called the TextureObjMask.  Not sure that's exactly what you're looking for... 

Best Regards,

[Anonymous]

object 1 is a visibility "mask".. object 2 when passing through becomes visible (as it enters) and becomes invisible again when passed through to the other side. 

[Alfred.DeFlaminis · Accepted solution]

Hello @Anonymous,

Did the ObjMask work out?  I thought about it more over the weekend and I have 3 total methods for you..  (File attached.)

1) ObjMask texture as listed, used in Opacity slot.  Doesn't preview correctly in the viewport but renders fine.

2) Counter Animated Slice plane.  Animate the object moving, add a Slice Modifier, and set a key on the start frame and then use set key or autokey to re-place it in the same spot at the end frame.  The result is an apparent cutting/visibility of the object.  

3) Animated boolean set to intersect.  

Since this post includes more info and an example file I'll unmark my other post and mark this if that's ok with you.  (Thanks for marking the original solutions!)  

Best Regards,

[Anonymous]

youre awesome. 

having some issues with iray (render issues you are probably aware of) but this is definitely the solution. although i want to say it was simpler back in much older version of max. but yes this will work for sure thank you 

[Anonymous]

Actually this all use slice rather than using the large object as the mask itself. which might not work for this application. im thinking maybe they removed the method i was using back then?

I did look up "ObjMask" and cant find anything online or within max on that.

maybe it was boolean but cant figure out how to only reveal the inside object.

[Alfred.DeFlaminis]

Hello @Anonymous,

The first example (top view) is using the TextureObjectMask and it's all setup for you.  The last one uses boolean and I have setup the boolean to show only the inside objects in my 4th example in the file above.  Scrub the timeline to see it.  🙂    

I am not sure which method you were referring to in your OP, there's not enough details to nail that down.  Can you remember some of the steps?  Maybe the name of one of the operators?  Maybe it uses some kind of simple texture with an animated UV Map?  That would also work... 

Best Regards,

[Anonymous]

nope i dont remember anything but having 2 objects and one was set to be the mask for another so that when they intersect the it wouls start becoming visible within the bounds

this file is great and will definitely get me going now i just need to figure out how to make it work with iray.

thanks again.

[Alfred.DeFlaminis]

Hello @Anonymous,

Hey no worries.  I suppose you could also put an AO in the opacity slot of the material.  Might have to invert it depending on how you want to view which side does what.  When the box is inside the other box it'll be full black which would act as a kind of dynamic mask I suppose.  Whatever works!

If you have any questions I'll do whatever I can for you.  Thanks!

Best Regards,