Koziol: Dimitri

[cerbellum]

Had to model/render something for 3d modelling class at school, flipside, being one of my tutors , immediately told me I should try Vray for rendering, so I did.

My first try at it:


Comments and critics are welcome

Really like the community around here too, I've learned a lot in these 2 days I'm using Vray.

Greets,
Cer

[Bratwurst]

Very nice and great model! Rhino?

[cerbellum]

Rhino it is

[flipside]

Hehe, hi Cer!

The blurry stuff, is that blurry reflection or refraction? In both cases, try not to use interpolation, just lower the samples to 5 instead of 50 and your results will look much more realistic.

Also, which hdri map are you using? I think there are more suited maps that would create much cooler reflections. Maybe even no map but only some big self illuminated planes around the model.

Stick with Vray, it's the best!

regards,

flipside

[cerbellum]

The blurry stuff... I guess your talking about the frosted plastic on the shirt and weights, I just fooled around a little bit to get it 'almost right'.

Material settings:


Anything I should change to get it better?

Your absolutely right about the hdri map I'm using, right now it was just a blurred hdri from a brazil tutorial (but now I know better ). I'll try some different maps or planes and will post them later on.

Thx for the comment

Greets,
Cer

[percydaman]

8 subdivs for the refract is WAAY to low if your using interpolation. 50 is a good number (default) for interpolated. 8 subdivs would be better if you were using direct comp.

[cerbellum]

8 subdivs for the refract is WAAY to low if your using interpolation. 50 is a good number (default) for interpolated. 8 subdivs would be better if you were using direct comp.

In both cases, try not to use interpolation, just lower the samples to 5 instead of 50 and your results will look much more realistic.

?

[percydaman]

look at the subdivs on your reflect and refract section. both are checked for "use interpolation" but one has a "50" in it and the other has a "8" in it. The "8" is the reason your refractions have kind of a mangy look to them. You should raise it to 50 and rerender and it will look alot nicer.


Percy

[flipside]

Ok, some clarification about reflections/refractions:

Reflection color: it replaces a number for the amount of reflection. White is fully reflective, black is non reflective at all. By using color instead of greyscale you get colored reflections (of course).

Fresnel: polygons facing the viewpoint will reflect less than polygons facing more away from the viewpoint. For example on a sphere, the edges will reflect more than the middle part. All materials actually have this property, so in theory you should always check this option. The ratio of amount reflection between the polygons facing away and polygons facing towards you, is controlled by the IOR. The lower you go, the less reflection there will be on the polygons facing towards you. So for glass, you should use 1.3-1.5 for IOR, but of course this also affects the look of the refractions! Metals for example are not transparant, so you can play with the ior as much as you like. They are however very reflective also on the polygons facing towards you, so you need to use high IOR values (15 for example), or you could just leave the fresnell unchecked, so that all polygons will reflect an equal amount.

Glossiness: the blurryness of the reflections. 1 is not blurry at all, 0 is very blurry.

The look (or the accuracy) of the blur is controlled by the subdivs. The higher the subdivs, the smoother the blur will be, but the longer the rendertimes! Usually you can use 3-8 subdivs (if you don't use the interpolation, see further down). An important factor here is also the AA settings. if you use good settings, the look of the blurred reflections will be better of course. So it's difficult to predict how your blur will look like if you test render with AA turned off. If you adjust the subdivs value while AA is turned off, you will most likely end up using way too high values in your final rendering when AA is turned on.

Interpolation is a way to speed up the calculation of glossies. It uses prepasses like with the irradiance map settings to calculate the glossies for a low resolution image first and then figueres out where it needs more 'attention' to further calculate more detail in the glossies. When using interpolation, you need to increase the subdivs drastically! Also the interpolation settings are very important here. The parameters are the same as for the irradiance map. Refer to vray.info or this forum for more info on these parameters.
Imo, the interpolation method isn't usefull in many cases, but sometimes you can benefit a lot from it. It depends on many factors like the shape of the surface, the amount of detail that is required etc... Sometimes you need to increase the interpolation settings so much, that you better don't use it and simply use low subdivs value. Especially for reflection glossies, I rarely use it.

Max depth is the number of times a ray bounces before reflection calculation stops. The old example is when you stand between two mirrors and you can see yourself an infinitive amount of times. You can limit this amount in vray by using the max depth value and this can speed up rendering.

The exit color is the color vray assigns to the ray when it reaches the max depth value.

All the same can be transposed to the refraction settings. The IOR of course controls the amount a ray is bent after it goes through a transparant surface.

The fog color is used to make thicker parts of a transparant object darker then thinner parts. The fog multiplier controls the amount of the effect, just play around with this, you'll notice the effect immediately. This usually requires low values (0.05 for example) otherwise your object will turn black.

Affect shadows will make your shadows colored, depending on your fog color and multiplier. Actually, these are fake caustics!!! This is very important to realize, because for this reason, when you turn on caustics for any object in your scene, the affect shadows option is neglected!!! Otherwise you would render double caustics (the real ones and the fake fog ones). Altough an option to not neglect the 'affect shadows' while using caustics would be great...

For more info about refraction glossies, refer to richard rosenmans excellent tutorial yo ucan find here:
http://www.richardrosenman.com/vray_absorption.htm


Mmmm that's kinda it I think. Also remember that glossy reflection replace the highlight setting you're used to in max materials. These are fake highlights. Also here, I would appreciate a fake highlight option for vray materials!

So for your koziol object, I wouldn't use reflection or refraction glossy on the shiny parts.
For the non shiny parts, I would only use reflection glossies, not refraction ones. The material only gets blurred because the surface is rough, the internal material is exactly the same as the rest, so it's refractions are not more blurry.

I would love to fool around with that object too, do you mind sharing the model ?

I hope this helps a bit!

Regards,

flipside

[cerbellum]

Thx for the info, copying it right now .

I've upped the model so here it is.

Have fun with it and show us the results of course

Greets,
Cer

[cerbellum]

For the non shiny parts, I would only use reflection glossies, not refraction ones. The material only gets blurred because the surface is rough, the internal material is exactly the same as the rest, so it's refractions are not more blurry.

The surface isn't rough, I didn't add any kind of bumpmap if that is what you mean. I believe it's really due to the refraction that it's blurred and semi-transparent. Correct me if I'm wrong of course, but I did some testing without refraction and that I just couldn't achieve the result I wanted.

Greets,
Cer

[flipside]

Yes your right, it's not good with blurry reflection only... I tested it too and couldn't get good results. But I do believe that its refractions are blurry due to the rough surface. When you use a bump map (and no blurry refractions or reflections), you get a good result because actually this is what makes your refl/refr blurred in one time.

So you either choose for glossy refl/refr or use a very small bump map. Glossy refractions is always really slow if you want good results, that's why I prefer to use the bump map. I'll post some renderings soon!

flipside

[flipside]

Here's a rendering with a bump map for the blurry parts. I don't use glossy refractions here, only a bit glossy reflection to make them a bit more blurred.




Here's one with glossy reflections (subdivs only 3!) and glossy refractions (subdivs 30 and interpolation -4,0 clr=0.4=nrm).

I must admit I underestimated the interpolation for blurry refractions... They can be quite usefull! This render took only 1/4th of the time of the first one... I still don't like the interpolation for reflections on curved surfaces though, they always give a fake feeling imo.

I also noticed that reflections of the body you see in the bottom plate took very long to render. So a reflection of an interpolated glossy refraction seems to be something very hard to compute. (it's also hard to write...)

Here's the render: (the bottom plate is really to bright but I didn't want to rerender it)

[percydaman]

they are both the same image

EDIT...haha by the time i had posted, you fixed it

[flipside]

Hehe yep, I was too fast copy pasting the image link

Now i realize why the second one is so bright! I forgot to turn of the default max light... (that happens when you use the demo that doesn't save the render settings!)

bye!