Textured edges

[NormanHadley]

This may well be completely impossible within the rendering paradigm but I'm going to ask anyway...

When you render a textured object, Keyshot applies the appropriate bump map to the surfaces but the edges retain their smooth outlines. Is that fixable? In the example below, the casting has a rough surface finish but the silhouette remains super-smooth, which is a visual incongruity.

Any thoughts?

[TpwUK]

Hi Norman, bump mapping is achieved by calculating how light and shadows would look with a given surface type, the actual topology of the model is not altered in any way and a consequence of this is straight edges , another consequence are surfaces that look flat when viewed from angles that don't lend themselves to showing the detail achieved with the calculations of light and shadow.

The alternative to this is 'Displacement' mapping, displacement mapping alters the model physically creating high and low points according to the intensity of light given in an image to be used to create the displacement. Sadly KeyShot does not support this currently.

HTH

Martin

[DriesV]

...
The alternative to this is 'Displacement' mapping, displacement mapping alters the model physically creating high and low points according to the intensity of light given in an image to be used to create the displacement. Sadly KeyShot does not support this currently.

HTH

Martin

Isn't displacement mapping a b*tch to control on the tesselation level?
I've used it in other renderers and while the results can be amazing I find that displacement mapping can be very picky about tesselation type and density for it to work well.
What's your take on this, Martin?

Dries

[NormanHadley]

Hi Martin & Dries

I'm only an occasional user so I'm not looking for anything too complex. I'm just imagining a "roughen edges" checkbox in KS 5 that just slightly disrupts the clean edges - even if it was a randomised algorithm that didn't match the lumps on the bump-mapped surface to the lumps on the edges. It would be a purely cosmetic thing to help the eye suspend disbelief - just like the new cosmetic radii feature.

[Despot]

Isn't displacement mapping a b*tch to control on the tesselation level?
I've used it in other renderers and while the results can be amazing I find that displacement mapping can be very picky about tesselation type and density for it to work well.

Not only that, its computationally expensive as well I think - for example in MW turning displacement on triples the rendering time

J

[TpwUK]

Hi DriesV ...

You asked: 'Isn't displacement mapping a b*tch to control on the tesselation level?' = Hell yes

Your comment:
      'I've used it in other renderers and while the results can be amazing I find that displacement mapping can be very picky about tesselation type and density for it to work well.'

Spot on. The mesh density has to be dramatically sub divided by numerous levels to get really good results. Generating landscapes as in Bryce style is its strong point, but you know what artists and designers are like, they will try anything on anything and then think and ponder on how to achieve what it is they are after. Displacement is good for things like brick patterns so when viewed from perspective renders they dont look flat too soon, and being used as such, they don't require so much SubD work. But for the things like wood grain, this is better left and dealt with by bump mapping. It's a very awkward grey area, the simplest answer i can give is this, if you can model the detail, then do so, but consider your options ... e.g, a front grill modelled using poly-modelling may add something like 15kb to a scene, do the same in NURBS and watch it add 15Mb to the scene. They will both offer excellent close up render potential, but the NURBS model would benefit from simple plane and then to apply bump and opacity maps, the same sort of rules apply with displacement maps. Model the hard edges and then use bumps for adding realism. If the hard edges are too numerous and complex to model by poly-modelling, vertex pulling and sub dividing, then use the displacement route, but increase your mesh density accordingly until you have achieved your goal.

Hope that helps ...

Martin