Jump to content

Vray and Spec Map


monkeyman905
 Share

Recommended Posts

First off im going to appologise by asking help on a question that seams to have been covered more than a million times on here but its to do with Spec maps in Vray and which slot to put them in, i have search the site and read many of the Threds so please dont curse me.

The best explanation i have read is:

"It all depends on what affect you are trying to achieve. If you want some parts of the object more reflective than another part (say gloss tiles, and none reflective grout) then put maps in the reflection slot. If you want give contrete that half shiny, half worn affect, then I would put the maps in the reflection glossyness, because that is what would be affected in real life. The concrete has the same reflectiveness over all its surface, but some parts have been worn or polished more that other parts, so only the glossyness is affected."

To me that sounds pretty self explanatory. My problem is in practise it doesnt seem to work. I have made a book which has Gold leaf around the leather and i want this to have more specularity than the leather. Ive made my map and then added it to the reflection slot in a Vray material (i use 3D max btw). On adding it and then doing a test render it seems to just render out the Spec map and by passing the coulour map unless i turn the map % down. It doesnt seem to be adding any spec to the gold at all. Could someone help me please?

 

Also if i ask vray buffer to render a spec map its just black, all though i get a reflection map which is just the spec map on the model.

 

 

Thanks Phil

[ATTACH=CONFIG]46635[/ATTACH]

Edited by monkeyman905
Link to comment
Share on other sites

Hi Phill,

 

Its hard to guess why it doesn't work for you.

 

My suggestion is:

1. open a fresh scene with a HDRI in the environment map. (HDRI because it will be easier to see various reflections when the environment color is not solid)

 

2. place a teapot with chromatic material, place a checkers map in the reflection map. (you can press the "show standard map in viewport" button to see which part supposed to reflect and which are not.)

 

3. now you should understand how the reflection map is working...

 

4. open your scene and pick a chrome material with checkers map on the book, make sure nothing is wrong in your scene and the vray frame buffer renders the spec map...

 

5. if its all good you must work on your original book material...

Link to comment
Share on other sites

Hi Phill,

 

Its hard to guess why it doesn't work for you.

 

My suggestion is:

1. open a fresh scene with a HDRI in the environment map. (HDRI because it will be easier to see various reflections when the environment color is not solid)

 

2. place a teapot with chromatic material, place a checkers map in the reflection map. (you can press the "show standard map in viewport" button to see which part supposed to reflect and which are not.)

 

3. now you should understand how the reflection map is working...

 

4. open your scene and pick a chrome material with checkers map on the book, make sure nothing is wrong in your scene and the vray frame buffer renders the spec map...

 

5. if its all good you must work on your original book material...

 

 

I will try this now thank you.

Link to comment
Share on other sites

The 'highlight glossiness' is the equivalent to 'specularity' in the vraymtl. A setting of 1.0 will give no specular effect. A setting of 0.9 will give you a pinpoint specular as would appear on a glossy plastic. A setting of 0.2 will give you a dull rubber look. It can be unlocked from 'reflection glossiness' and controlled independently but will require a non-zero value for reflection amount in order to show up, where the higher the value is, the stronger the effect is. If you do not want proper reflections and just specular highlights, then you can disable 'trace reflections' and the material will render faster.

Link to comment
Share on other sites

I thought I recognised your initial quote ;)

 

Anyway, also dont forget that specular only happens when the light source is seen in the reflection, and only when the material has a Highlight Glossiness of less than 1. The specular pass basically shows the reflection of the light its self. Sometimes the angle of the object can determine whether an object has specular or not.

 

Try dropping in a large vray light where you would expect to see it in the reflections, and see what happens. I find HDR's arent very good in these situations because you end up spending more time adjusting and messing with the HDR rather than the materials!

 

Deano

Link to comment
Share on other sites

Haha The qoute helped me a lot to understand vray materials. I've final got it all working and the spec map is now rendering off. The only issue now is it seem to be effecting the diffuse map to much, as the gold colour I wanted to have the spec is been dulled out a bit and losing its golden colour! If I lower the map percentage in the reflection slot to 40% it helps but still washes out the colour! Bit annoying, going to try lower the lights and Clare if that helps if not see if I can correct it in photoshop with the maps I've rendered.

 

I'll post the results when I get home.

 

Thanks again for everyone's help

Link to comment
Share on other sites

If it's gold material you're going for, remember it's dieletric... so it should have some of the difuse color in the reflect color. Is that it?

 

 

Im dont quite under stand,

 

This is my set up, with the material, spec map and the final image which is produced, not like the gold in the top right hand corner that im aiming for

 

[ATTACH=CONFIG]46792[/ATTACH]

Link to comment
Share on other sites

Your "spec map", usually named "reflection map", is a grayscale map... put some golden color color on it (not over the black part, of course) and that's it. And set fresnel on reflections with an IOR of something like 15. At least that's how I would go about it... And make sure you got at least some bump in there.

Edited by dmv79
Link to comment
Share on other sites

Your "spec map", usually named "reflection map", is a grayscale map... put some golden color color on it (not over the black part, of course) and that's it. And set fresnel on reflections with an IOR of something like 15. At least that's how I would go about it... And make sure you got at least some bump in there.

 

That's it just add some golden color? Is a reflection map and spec map different then?? I thought they were both the same just different name and had 2 be grey scale?? Then the white area is reflective and the dark are is not reflective

Edited by monkeyman905
Link to comment
Share on other sites

The reason I called it "reflection map" is because it's in the reflection slot. If it was in the reflective or highlight glossiness ones I would then call it "specular map" (depends if they are linked or not). The specular maps should be grayscale and are a subject of their own and a bit tricky, where you define were you want it to be more or less glossy (look it up, it's worth the time). The reflection map not necessarily. Some materials have their color derived from the difuse color, and some from its reflections. In this case, it comes from its reflections. So you should tint the reflection color or map towards your goal (note that the brightness of the color still influences the reflection amount). Other then that, the specular will be more or less interesting depending on your geometry. In this case, I would start with a simple bump. If I was not pleased, I would try a normal map. If even then I was not satisfied, I would go for displacement. If you still don't get what you want, I'll be glad to take a look at your max file.

Link to comment
Share on other sites

One more important thing. Speculars need a direct light source. So in the teapot case, you should have the HDRI in a vray dome light. If it's in the renderer environment slot, you are only getting the indirect lighting, wich doesn't generate speculars. If you place say an omni light where you would see it in the reflections, you're gonna get a whole lot of speculars... maybe more than you would like.

Link to comment
Share on other sites

I am definately in agreement on the need of a bump map here. The example photo that you are aiming for that was posted several threads up has some very prominent bump effect from the embossing on the cover, and in these areas where the surface is not flat is where highlights are being picked up. To mimic this you can take the map you are using as a mask, invert it and blur it a little in photoshop. How much? Well I would save out several variations and try them all out until I found one that I was happy with. You might also need to shift the midpoint in levels to push it halfway back towards white (if you inverted in PS) to move the gradient that is created back into the gold embossed area.

Link to comment
Share on other sites

One more important thing. Speculars need a direct light source. So in the teapot case, you should have the HDRI in a vray dome light. If it's in the renderer environment slot, you are only getting the indirect lighting, wich doesn't generate speculars. If you place say an omni light where you would see it in the reflections, you're gonna get a whole lot of speculars... maybe more than you would like.

 

If you could have a look that would be great I have tried everything! Different lights, maps, colours and still no luck!!

Link to comment
Share on other sites

I am definately in agreement on the need of a bump map here. The example photo that you are aiming for that was posted several threads up has some very prominent bump effect from the embossing on the cover, and in these areas where the surface is not flat is where highlights are being picked up. To mimic this you can take the map you are using as a mask, invert it and blur it a little in photoshop. How much? Well I would save out several variations and try them all out until I found one that I was happy with. You might also need to shift the midpoint in levels to push it halfway back towards white (if you inverted in PS) to move the gradient that is created back into the gold embossed area.

 

Thanks for your comment. I've got a vray displacement mod at the top of the stack set to 3D mapping. Looks like the settings are not high enough! I'll ramp them up to get a better emboss and hopefully it will look more like the image. Just been trying to get the gold correct first

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...