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Foroloca

Avoid distortion between objects

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Foroloca    1

What you see in the screenshots is a framework (red) and between the frame transparent plates that fit exactly. When rendering you get some 'distortion' between the frame and transparent plates, is that something that is inevitable or not? I could size the plate a fraction less so the aren't touching on exact the same coordinates, but i was wondering if that is really necessary when modeling so precise?

01.png

02.png

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Rectro    536

Iv seen this kind of issue before yes but only in some cases for glass where placed dead on top of another object (sharing the same space) with refraction againts other objects it can be worse.  The screen shots your showing are not renders right, so what does it look like in a render as it could just be a OpenGL viewport thing.  Also I dont know what lighting your using, GI Im guessing as you have no scene lighting?

 

When you get this, its called Z fighting where two objects share the same space.  To get around it overlap one object over the other as the rays dont know which one to shade in the same space so the first object that the rays hit get shaded hence a bad shading error.

 

Here is a file,  Your see green size the problem is gone.  Here is some more info on it.

https://en.wikipedia.org/wiki/Z-fighting

 

 

Dan

z fighting.c4d

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Foroloca    1
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  • I didn't setup the total scene yet so no lights, background, floor etc. did test it just now and with that on it still has refractions. Sizing it just fraction smaller removes the refractions, but like the dimensions on-changed if possible just was wondering if there is a solution. Material is just color with transparency on, not specific glass or plexiglass going to test that now. If you have ideas on how to avoid this please share thank you

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    Rectro    536

    Just updated my post, have a read on Z fighting.  Push the glass into the frame of the object then the frame gets priority when the rays get calulated.  I get this if I make a human eye with two shells outer being transparent, if one is intersecting into the others space then I get these issues. Download my file, your see Green side has no issues.

     

    Dan

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    Foroloca    1
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  • That is exactly what happens, learned a bit more! So sizing is the solution so they don't share the same space when using transparency. Will overlap the plexiglass plates a bit. You are a star! Thank you ::): 

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    Cerbera    1,274

    Just to add, this is also the reason that when making liquids in glass you should always make the liquid slightly intersect the inner surface of that glass...

     

    CBR

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    Foroloca    1
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  • 2 minutes ago, Cerbera said:

    Just to add, this is also the reason that when making liquids in glass you should always make the liquid slightly intersect the inner surface of that glass...

     

    CBR

    Yes seems totally logic if you know the Z-fighting issue, locked in my brain now thanks to your help. Forums are great thing! :compChat:

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    Rectro    536
    28 minutes ago, Cerbera said:

    Just to add, this is also the reason that when making liquids in glass you should always make the liquid slightly intersect the inner surface of that glass...

     

    CBR

    Yes indeed, either have the liquid be smaller or larger than the inner glass, never the same.  In some render engines it shows black,  one could be mistaking it as reflection depth not high enough.  

     

     

    Dan

    Z fighting.jpg

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    Vizn    42

    From an architectural perspective, no window in existence is built this way. Glass is typically 'encased' by the frame. So, for realism, if you push the glass edges into the frame, you must also model a channel in the frame. It's a small bit of detail that helps sell realism in renderings, when necessary. Not to mention it hides the co-planar artifacts you're getting.

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