Strange artefacts in internal reflections

I have a Keyshot question… I’m not sure if you guys have seen this in other packages?

Here’s a typical render of the horn I did a few weeks ago from my original Rhino model - no problem:

Now I’ve remodelled it in T-Splines:

It works fine:

until I add a reflective material and then it all goes a bit odd - the annoying thing is that it happens with both models and no amount of tweaking or turning everything up to 11 makes a difference:





Now here’s a standard environment map:

Any idea why this is happening?

I suspect this is due to the way keyshot is interpreting the normals.
Can you convert the shape into a mesh and does that act the same?

Did i read correct that this is only with the new tsplines model and in rhino it displays correct, but not in keyshot?

If so there likely is an issue with keyshot not correctly interpreting the tsplines geometry hence my suggestion to convert to mesh in Rhino.

From there it could be either keyshot or tsplines need to be optimized.

Edit: I just reread your post and I might have made a wrong interpretation. I now suspect your model in keyshot to have too many internal reflection. How about setting only a single refelection pass (if that is a thing in keyshot).

-Willem

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I think it’s correct. What you’re seeing is reflections of reflections ad infinitum (or at least a bunch of times). If the reflections are perfect then there will be no blurring and no darkening.

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Thanks guys,

I think that must be it - I don’t see any way of limiting the number of reflections within keyshot for a single surface but that could be just my limited knowledge:




Shot in the dark (no pun intended):
How about setting the material to something other tan a 100% reflectiveness,
It would lessen the reflection intensity each bounce

-Willem

With metal you can’t set the refraction index you can only add roughness which basically adds noise - by the time the artefacts have gone there is little or no reflectivity.

If it’s a shiny plastic surface then it’s fine… Just doesn’t work well on metals.

I’ve been through a range of advanced materials and tried tweaking it but it always comes out as either muted or shiny with those artefacts.

I spoke to a mate who writes for 3D World and uses VRay in Max - he had the same results… interesting artefact.

Basically the only way to stop it is to split the inner face and put a rough surface on the opposite side - do the same on the other and render to layers… Comp the images in photoshop and cheat it.

It’s a bit of a pain but it should work - once I’ve done it I’ll post some images - for now I’m detailing the components to be printed (this thing is over 500mm long!)

Cheers

Andy

Examples from VRay:




Congratulations, good you got it worked out.
Nice to see the ‘good ol’ max teapot.

You did get me curious, what you need a 50cm long horn for…

-Willem

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