rendering perforation

[tonguey]

i'm using 3dsMAX 2009 in VRAY and i'm having issues rendering metal perforation. i have a perforated metal facade (similar to mesh), with materials/windows behind the facade. i want to be able to show varying light qualities and materials behind the metal through the perforations. how would i be able to achieve this? here's a very rough rendering of what i have right now:

 

 

i'm only able to show the facade without anything behind it. any suggestions? thanks!

[innerdream]

I suppose you could make a .png with transparent holes and map that to geometry?

[ronll]

The problem with perforations is that there usually is not enough resolution to handle it. Unless you use REALLY high res, there just are not enough pixels to accurately render the holes/nonholes areas. I usually fake it (I'm not using 3DMax) with some sort of semi-transparent material with a noisy texture. Depending on the distance from the camera, it is not always successful and continues to be a problem for me.

 

What I should probably do is take a digital photo of real perforated material at the same res as my renderings and see how the camera renders it, then try to emulate that.

[Devin Johnston]

It depends on how big the holes are, if they are of descent size then all you need to do is create an opacity map and attach that to you metal material. The one draw back to that is the material will not have any thickness, but that kind of material is usually pretty thin and it's not really noticeable.

[CRD]

An alternative to mapping is to use the vray displacement set to 0.5 inch with the water level set to 0.1 inch. The water level will delete any mesh below it, so you will get physical holes. The positive is you are not messing with transparency and it has a thickness and will sometimes catch specular highlights. A down side is that if you see the back of the mesh, it's still just one sided, it has not been "shelled" or made solid.

[ronll]

Isn't there still a problem of not having enough pixels in the final image to show it? Unless of course it is a very large holed perf or very close to the camera.

[Chad Warner]

An alternative to mapping is to use the vray displacement set to 0.5 inch with the water level set to 0.1 inch. The water level will delete any mesh below it, so you will get physical holes. The positive is you are not messing with transparency and it has a thickness and will sometimes catch specular highlights. A down side is that if you see the back of the mesh, it's still just one sided, it has not been "shelled" or made solid.

 

I use this method all the time for perforations if I'm going to be close to it at some point. If I know I wil be far away, I'll just use an opacity map.

[Nic H]

you cant see every hole in a photo, so you wont be able to see every hole in a rendered image.

 

make sure your blur is set to 0 on diffuse, opacity and bump.

 

if you render the image big enough (say 5k) you will be able to see the perforations provding they are of a correct scale

 

id put a few duifferent intensity/coloured vray lights or vray light mats with photos in them behind your different gauge meshes.

[tonguey]

thanks for all the speedy replies! i'll try some of the techniques mentioned and i'll post up the results as it progresses

[danb4026]

getting to your vray displacement solution....you do not get perfectly round or square "perforations" that way...at least I don't. Is there a setting that would make for perfectly round perforations?

[CRD]

getting to your vray displacement solution....you do not get perfectly round or square "perforations" that way...at least I don't. Is there a setting that would make for perfectly round perforations?

 

The quality of the hole in the displacement is connected to the quality of the displacement settings. I find on precise stuff like this that the 2D mapping is much cleaner. The 3D mapping ends up too chunky, which is fine for rocks and the like.

 

Switch to 2D mapping and match the resolution to the pixels in your map and it should be smooth.

 

As for the questions about will it show up, I prefer to create it in a way that mimics real life and then let the VRay sub pixel sampling sort out the detail. This way you can zoom in or out, or animate as you please.

 

But to counter my own argument, sometimes if it's backlit and you are going to be far enough away, I'll blend between a vraylightmaterial and a metal screen. So there's no transparency involved, it's just mapped to look that way.