topic Please help me set-up a decent looking caustics (Vray)? in 3ds Max Forum

Please help me set-up a decent looking caustics (Vray)?

Anonymous — Sun, 06 Mar 2016 12:07:04 GMT

I'm having a problem with my cuastics renders. they look so ugly and nowehere near how the final output in this tutorial looked.

here's the tutorial link

http://cienel.net/3d-studio-max-tutorials/vray-realistic-caustic-effect-in-3d-studio-max/3

I tried to follow all the settings in the tutorial above and so far my renders look different.

here are the pics: (affect shadow on) why is there no light passing through the back? my directional light is in front (near my camera)

in the next pic below, i unchecked the affect shadow at the refraction tab

light passes through but the shadow of the object is nearly not noticeable (unlike the one in the Tutorial link)

my caustics also lok so noisy. i even set up the caustics setting to high values. my settings are: Search dist 100, max photons 600, multiplier 1.

Re: Please help me set-up a decent looking caustics (Vray)?

kgokhangurbuz — Tue, 08 Mar 2016 02:05:34 GMT

Hello;

Your object size must be the reason for that, also the light sources photon multipliers and / or refraction IOR / fog color may be too.

Caustics are results of refraction of light rays in the object, which has refraction amount.

You may try:

-Scaling your object to half of its current size

-Scaling your object to two times of its current size

If one of these get you closer to the result of tutorial you watch, then it's a size issue.

Please keep me updated about this, so we can figure your problem.

Best regards;

Re: Please help me set-up a decent looking caustics (Vray)?

Anonymous — Tue, 08 Mar 2016 23:37:08 GMT

hi bro, thanks for the reply.

i still couldn't make those soft caustics, and they're not appearing at the back of the model. my light is right in front (near my camera) here are my renders. half sized, then double sized.

Re: Please help me set-up a decent looking caustics (Vray)?

kgokhangurbuz — Wed, 09 Mar 2016 00:06:54 GMT

Hello;

Can you please save your file as 3ds max 2014 and share with me so i can
have a closer look and help you.

Best regards;

Re: Please help me set-up a decent looking caustics (Vray)?

Anonymous — Wed, 09 Mar 2016 10:34:23 GMT

Re: Please help me set-up a decent looking caustics (Vray)?

kgokhangurbuz — Wed, 09 Mar 2016 18:54:49 GMT

Hello;

Your save file is not saved as 2014 so i can't open it, can you please re-upload as 2014?

Best regards;

Re: Please help me set-up a decent looking caustics (Vray)?

Anonymous — Wed, 09 Mar 2016 22:48:16 GMT

Re: Please help me set-up a decent looking caustics (Vray)?

kgokhangurbuz — Thu, 10 Mar 2016 01:19:14 GMT

Hello,

I've examined your scene. First of all, your object is huge, this is the main reason that you arent getting physically accurate results.

Remember, V-Ray always uses real world approaches for your scenes, for cameras, reflections, refractions and everything. For any object in your projects, try to model them in real life sizes, or scale them close to what it should be in real life sizes.

Here is the result of default Caustics parameters with your scene, after my rescaling (I rescaled your object of interest to around 10cm's high, Uniformal scale to not to change its proportions):

And here, what happens with some fine tuning;

Also, your Direct Lights Intensity amount affects this calculation directly, increasing it is highly recommended in caustics calculations. With the Include / Exclude lists of 3ds Max, you can exlude your ground object from illumination of this high intensity light source. Also, Standard Lights do not have Decaying as default, simply make them "Decayed" by going to Direct lights modify, Intensity / Color / Att. rollout, change Decaying type to Inverse Square or Inverse (You can see their differences by rendering both and comparing them).

I Also removed your VrayHDRI from your Render Setup > Environment > GI Override by the way.

Calculating caustics quality is also a matter of your Render Setup / GI quality, amount of other light sources etc. But in your case, increasing your GI engines sampling amounts will also help you. Your light sources distance also matters when it's about caustics.

I'm sharing the scene with you, as scaled, and tuned, saved as 3ds max 2014 so you can inspect the scene for what i have changed majorly in the Caustics setup.

I hope i could have helped you. If you have more questions, please don't hestitate to ask.

Best regards;

Re: Please help me set-up a decent looking caustics (Vray)?

Anonymous — Thu, 10 Mar 2016 13:05:52 GMT

hi kgokhangurbuz, thanks for your solution. can i please ask a follow-up question? how do make the glass' shadow more evident? (like the your first posted picture?) but i also want the scene to be bright (like your second picture)?

i'm really sorry 'coz im such a noob, idk what im doing in 3ds max.

i tried making another vray light at the back of the directional light but it still doesn't cast a shadow.

Re: Please help me set-up a decent looking caustics (Vray)?

kgokhangurbuz — Thu, 10 Mar 2016 23:51:38 GMT

Hi;

There are many approaches about what you have asked, i will just mention few basic and most common ones;

-If you are creating caustics with standard lights, you can always increase the shadow density from Direct & Spot Lights parameters from Shadow parameters rollout of lights modify panel.

-You can tweak your physical camera's exposure to balance dark and bright areas

-You can render shadows as seperate render element and use Autodesk Composite, Adobe Photoshop or PDPlayer for tweaking

-In some cases, some parameters under Rendering > Render Setup> V-Ray > Color mapping such as Burn value, Multiplier, Dark Multiplier, Bright multiplier can be used to tweak dark and bright areas.

For the brighter environment, you can always use a VRayLight > Dome for a homogenic environmental light source, changing the Multiplier amount of it simply affects your whole environment. In such scene, where your caustics are being calculated with a specific light source, it's preferred to turn off Generate Caustics from Dome Lights Right Click > VRay Properties.

Yet again, you can use your Camera's exposure parameters such as f and Shutter Speed (If it's a physical Camera) to achieve the brightness you want.

Hope these help to you 🙂

Best regards;