Experiments

[jahnme]

Hi,

 

I really like the new render engine for v10. I have tested some of the new features and wanted to share a few experiments.

 

 

Volumetric light allows you to see the beam of light from a spotlight.

 

 

 

Gels are bitmaps that can be applied as filters to lights.

 

 

 

You can also add a glow effect to a lightsource.

 

 

 

Regards,

 

Jonas A

Edited November 8, 2007 by jahnme

[tlehnhaeuser]

Nice job Jonas, keep up the explanations.

tom

 

BTW, Gels have been there since V1

[jahnme]

Thanks Tom, I didn't know the gels where that old... Still I think they look nice together with the volumetric lights

 

Jonas A

[jahnme]

Hi,

 

Here's another experiment.

 

Emission light source. The object in the middle is generating light.

 

 

 

Jonas A

[tlehnhaeuser]

Jonas,

I seem to struggle with this one, maybe you can help.

 

I am trying to a super high gloss finish on object ( to almost look wet) but for some reason this eludes me. Any ideas?

Thanks

Tom

 

[jahnme]

Hi Tom,

 

The easiest way for me to look for a solution would be if you could post an example as .ics. If the information is sensitive maybe you could change the part in the scene. The solution could be to tweak both the lighting and the material.

 

Jonas

[tlehnhaeuser]

Jonas,

Not workign on anything particular , your example would be good enough. But I resort to the old rendering ways with reflection at 95% on a object with has an image refelection set. Howeve, that really gets me to about 80% where I want to be.

 

I'n not sure if using shaders and global illumination is where I need to expore to get better results.

 

For example on your last image, the red objects are very close to what I'm looking for. Could you post that .ics file for me to look at?

Thaks

Tom

 

[tlehnhaeuser]

also, my objective is like having a clear coat gloss finish paint on a car

[jahnme]

Hi Tom,

 

I'll be happy to post a scene once the final version is out, but my beta version scenes are a bit buggy for some reason, so I'll explain this one with images instead.

 

It's quite simple actually, the secret is in the fresnel value on the reflection tab, but first I'll show the finish tab. As you can see, the highlight intensity and highlight spread are down to zero.

 

 

Here's the reflection tab. Reflection is 100, while the fresnel value is 0.4.

 

 

The image below was created in a default scene (no GI or anything fancy) with a white background. The object to the left has a fresnel value of 0.4, the one in the middle has 0.8 and the one on the right has 1.0. If you ask me, I'd go for the one in the middle

 

 

Having said all this, I'll have to admit that this is no real carpaint, but it is as close as I've gotten in IronCAD. You would have to use a shader with mulitlayered colors to achieve a true carpaint. Maybe it's possible to achieve that, but I haven´t figured it out. Cary?

 

Regards,

 

Jonas A

 

 

[tlehnhaeuser]

Thank Jonas,

I'll try your settings.

 

The image shows my attempt and I found that if you use reflection, 3D background and most importantly the Ward setting on the Finish of a part, you get what my image shows.

Thanks

Tom

 

 

[Cary OConnor]

Hi,

 

Sorry I didn't even see these post until just now.

 

They look great by the way.

 

The Diffuse and Specular BRDF settings can make a big impact on the look of the material. We currently do not have a good carpaint shader yet. It requires a meta shader to really get the look. The Ashikhmin BRDF in both the Diffuse and Specular can give a close result to a car paint. I think I have an example some where. If I can find it, I will post it.

 

Cary

[Cary OConnor]

Example below shows default BRDF settings.

 

test2.bmp

 

 

Example below shows Ashikhmin and Fresnel

 

test.bmp

[Mike Allen]

I'm doing a little testing to see exactly which controls have what effect, when it comes to reflective surfaces - and it seems to me that once you set reflection to 100, all your other setting choices become much simpler.

 

The fresnel setting has a direct effect on the amount of color saturation (0 = 0% saturation, 1 = 100% saturation) & the Diffuse Intensity setting has an inverse effect on the amount of black in the color (0 = 100% black, 50 = 50% black & 100 = 0% black.)

 

As far as I can tell, once reflection is set to 100, none of the settings for Highlight Intensity, Highlight Spread, Diffuse BRDF, or Specular BRDF have any effect.

 

Ambient Intensity has a moderate effect on the contrast of the shading - changing from 100 to 0 makes the shading darker.

 

(Diffuse Intensity = 0, Ambient Intensity = 0, Fresnel = 0.80)

(Diffuse Intensity = 100, Ambient Intensity = 0, Fresnel = 0)

(Diffuse Intensity = 100, Ambient Intensity = 0, Fresnel = 1)

(Diffuse Intensity = 100, Ambient Intensity = 0, Fresnel = 0.80)

(Diffuse Intensity = 100, Ambient Intensity = 100, Fresnel = 0.80)

[Bryan Cargill]

Cary asked me to give some details on the relationships between ambient intensity, diffuse intensity, reflection intensity, and fresnel amount.

 

The ambient intensity of a material scales how much the material responds to the ambient light of the scene (under Scene Properties/Rendering/Ambient Light Level). An intensity of zero means the ambient light doesn't effect the material at all. An intensity of 100 means the ambient light effects the material at full intensity. The actual effect on the material is proportional to the power of the scene's ambient light. If the ambient light power is zero-- the materials ambient intensity is meaningless. Here, the ambient intensity of the material is varied from 0 to 100. An ambient light power of 100 is sued to demonstrate the effect.

 

As the ambient light is made brighter, the scene will become washed out-- contrast will diminish. This is becasue the ambient light is coming from all directions simultaneously and evenly. Ambient light can be thought of as an extremely crude approximation of global illumination. Here, the power of the scene's ambient light is varied from 0 to 100. The material has an ambient intensity of 100.

 

The diffuse intensity is very similar to the ambient intensity-- except that it describes how much the material responds to non-ambient light sources (point, spot, directional, etc). A value of zero means the material will behave as if there is no light at all. A value of 100 means the lights will effect the material fully. It really is scaling the lights brightness, for just that material. Here, the diffuse intensity is varied from 0 to 100.

 

Reflections are a bit more complicated. The final appearance of a reflective material is the result of a combination of the diffuse+specular mixed with what is reflected. Lets call the ratio at which these are mixed the effective reflectivity. A value of 0 means no reflection (only diffuse+specular), a value of 100 means total reflection (no diffuse or specular). Note they are mixed-- not added together.

 

So what determines the effective reflectivity? It is not necessarily the material's reflection intensity setting. It is based on a combination of reflection intensity, fresnel amount, index of refraction, and angle of incidence (angle between how we look at the surface and its surface normal).

 

The fresnel amount controls the behavior of the reflection. A value of zero means the reflection is totally perfect and constant over the surface. A value of one means the reflection is totally fresnel based. Fresnel based reflection calcualtion increases in intensity as the index of refraction goes up and as the angle of incidence goes up. This means that surfaces viewed at glancing angles become more reflective.

 

This is the way many materials work in real life. Using fresnel based reflections, the outer edges of a sphere will appear more reflective than the center. Consider looking through a glass window-- if you look directly in the window you will see little reflection-- but if you walk close to the window and turn your head to look at it from the side (a glancing angle) you will see almost nothing but reflection.

 

Here is an example of the simple case, fresnel = 0, perfect constant reflection. In this case- the effective reflectivity does indeed equal the materials reflection intensity. Here the reflection intensity is vaired from 0 to 100.

 

In this example, we vary the fresnel amount from 0 to 1. This shows the effect of blending between perfect and fresnel based reflections. The index of refraction is 1.5 which gives a weak fresnel based reflection. Reflection intensity is 100.

 

Fresnel based reflections do not have to be weak. Increasing the index of refraction will increase the amount of light reflected. Here the reflection intensity is 100, and the fresnel amount is 1. The IOR is varied from 1 to 20.

 

[Guest rzito]

Hi All,

 

All these images are fantastic, how about Ironcad creating some tutorials or demos that can walk you through some of these advanced rendering methods.

 

I'll be going through all postings in this subject, and experiment on my models.

 

Looks like many late nights on the agenda.

 

Best Regards

[sbuchanan]

This stuff is great! I would love to see some "advanced renderings" documentation released along these lines. I moaned and moaned about the getting the new rendering enhancements, and now that they are here I realize how much I have to learn.

 

Nice work guys.