Reflection Map Shine

[papaf1]

I know this has to be another easy fix like so many other problems I have, but I’m using a reflection map in a standard material and it needs to disappear when it move out of the light into the darkness. The problem is it’s acting like it’s got self-illumination turned on or it seems like it’s got a light shining on it, but even when I turn off all the lights it’s still shining. Is this something to do with using a reflection map, and is there something I need to do to get it to respect the light source shining on it, or not shining on it?

[Francisco_Penaloza]

You need to place a raytracer shader in the reflection slot, then add any bitmap.

[Alfred.DeFlaminis]

Hello @papaf1,

It's nice to see you again!  I'd like to help with this issue.  Did @Francisco_Penaloza's advice help here?  If not, is it possible to attach a simple scene that demonstrates this problem?  If that isn't possible, can you please tell me which renderer you are currently using?  Thank you very much for doing so.

Best Regards,

[Alfred.DeFlaminis]

Hello @papaf1,

I just wanted to follow up here, any progress on your issue?

Best Regards,

[papaf1]

Sorry for the delay, I'll be back home tonight and I'll try your suggestion.

[Alfred.DeFlaminis]

Hello @papaf1,

No problem!  Just didn't want you to think I had forgotten about you.

Best Regards,

[papaf1]

The suggestion didn't help. I'm attaching an example of what I'm talking about. The example has 2 Material slots, (Chrome1) is the way I was doing it and (Chrome02) is the suggestion given above as I've interpret it. The chrome should fade off into the darkness when the light isn't shining on it. Both options don't do this.

[Alfred.DeFlaminis]

Hello @papaf1,

Thank you for posting the file.  Sometimes it does get hard doing everything theoretically and having a file is great and so much faster.  What is happening here is that you have the map plugged into that reflection slot, which tells 3ds Max to use this map as what is being reflected by that shader in the case that there is no object closer to reflect.

What that means is that if the shader finds nothing nearby to reflect, it will then extend out to the 'world environment' and reflect that, unless you have a texture override somewhere, which you do.  (That's why that area of the shader is called "Background").  So in this case it's your texture it will see instead of the environment.  Even without lights on, it's seeing that texture as something it should be reflecting and so it is doing that. This is also why the shader has an option for environment in case you want the whole scene to see that map.  I have attached another file here with a simple box blocking the reflection rays to the environment (with the lights off to make it easier to see quickly).

Here's how you can test this.  If you change your reflect map to "Environment Settings" and press render, you'll get black.  Then, if you paste your texture into your environment slot and render again, you'll get the same render you're getting right now/start of the thread.  (And you'll see it in the background as well.)  So the key here is putting something between that object and the environment at the proper angle needed to block the reflections you don't want.  It can be textured, or not... that's up to you.  

I hope this makes sense, and if you have any questions please let me know.  

Best Regards,

[papaf1]

I appreciate the suggestions and I understand about putting a reflection item in the scene, but my attempt is to have a chrome material that looks like chrome even when the environment is black and have the material effected by the light. I want it to shine when the light is on it and then fade away when the light isn't on it. The reflection Blocking file you gave does go away in the distance but it's not effected by the light and when the light is on the chrome effect or the reflection flattens. It doesn't look very good at all. I'm just looking for another option to get this result, because everything I've tried or seen doesn't work.

[Francisco_Penaloza · Accepted solution]

You need to place a raytracer shader in the reflection slot, then inside the raytracer shader place your fake reflection texture (bitmap) in the background section. Also be sure that in your material options, under Extended Parameters, Reflection Dimming is checked on.  There you can control how much "fake" reflection your show and how much that material will be affected by the environment or lighting.

Default it is off, not sure why. But if you checked on it should work as you need.

[Alfred.DeFlaminis]

Hello @papaf1,

The scene I sent wasn't an artistic one, but just to prove what was happening.  If you put a fake environment around everything, the material is going to reflect that environment.  Technically chrome in a dark space will be black.  So really you want to fake realism which can be tricky at times.  For example:

If I sit in shadow and take my phone screen (when off) and angle it toward the city skyline, I'll see that city skyline reflected in my screen despite not having any direct light on the phone screen.  This is what is happening to you.  Now it's just a matter of blocking those reflections in an artistic way.  You can do it with a mass, you can do it with a reflection card maybe, or some other method.  From a technical perspective, this is working properly.  

Other options might be to render in passes and composite them together to fade the reflections, or you could multiply that environment by a gradient on channel 2 or something, all that is up to you.  I've attached a scene here with a gradient mapped on channel 2 multiplied by your reflection map as a reference. I hope this reference helps.

Best Regards,

[papaf1]

Thank you Alfred, this looks great. I really need to study up on the Composite material. I can use this method to get the results I was looking for. Thank you again sir.

[papaf1]

Alfred
I know it's not that hard, and at risk of looking stupid, I'm trying to create the same material from scratch and it's not coming out the same. Can you please give a step by step on what you did to create this. Going in to your texture and setting everything the same isn't working. I know, it should be simple.

[Alfred.DeFlaminis]

Hello @papaf1,

I would be more than happy to help.  I have attached a movie below that should detail the process for you.  I hope it helps and feel free to ask any questions if it does not.  Note that there were other things I could do with the mapping like turn off tiling on the gradient, scaling it to be bigger, etc. but the concept still stands.  

Best Regards,

[papaf1]

Hey Alfred, very nice job on the video. It helped a lot. My other question is what happens when you place a base or a floor in the scene. It looks like the Gradient Map does something strange when it gets to the darkness, it's like it reverses again. Also, the UV Map is set to View Align, and it works very well but what do you do if the camera is animated? I love this approach Alfred, I'm adding a new file that shows the next phase. Thank you again for all your help and suggestions.

[Francisco_Penaloza]

I am still struggling to understand this, I think I am missing something.

If you want to "fake" a reflection in Scanline with Standard materials you just need to place a raytracer shader on reflections, then use your texture under environment and be sure that Reflection Dimming is checked on. 

That's all, your material will react to the lighting, no matter what position the camera is. I been doing this for years, always works the same.

The work around explained here is pretty cool for sure, but IMO is not necessary.

again unless I am missing something, it should be a more simple solution that that.

[Alfred.DeFlaminis]

Hello @papaf1,

With more objects in the scene, it does make more sense to use the dimming as proposed by @Francisco_Penaloza in this case, that would account for animated cameras.  For a single object in space the one I shared does work but it doesn't account for the newer variables.  I didn't realize there would be a floor, I probably wouldn't have suggested what I did.  So, that's on me.  I've attached 3 scenes, 1 with Francisco's method, 1 with A&D Chrome, and 1 with a non-view aligned mapping.

I sort of led you astray and I should have asked if more was going to be part of the scene.  With the increased complexity, Francisco has the best method.  (Attached a scene with that method as well.)

That being said, you don't *have* to use View align, that was a quick and easy way for the simple scene.  You can also do a standard mapping, works just the same.  I like view align sometimes because it's super fast, but I would go for the method that is the easiest.  In post you could comp out the reflections fading into the distance if you render to elements.  That is what I would do as it offers the most control and if the client feedback has changes to that falloff it's faster to perform.  (Chrome scene) 

Best Regards,

[papaf1]

Francisco, I'm using Mental Ray and the texture doesn't fade away when the light doesn't shine on it. It's not being effected by the light. Look at the 2 files I've sent. The reflections do not fade away when the light isn't shining on it. If I need to check off a check box for reflection dimming then where is the check box? This problem has been described in painstaking detail above, I don't know how to explain it any other way. If this can't be done that's fine, if it's as simple as a check box then that's even better. But it should be very clear that I don't know where this check box is. I guess I don't have as much experience as you.

[Alfred.DeFlaminis]

Hello @papaf1,

It's in the top level of the material under Extended Parameters.  I also included a file with that enabled that may help in my previous message.  If it makes you feel any better, I had to look it up too because I'd never used it before.  Apparently its primary use is this exact scenario.  I've always done all that in post...  

Best Regards,

[Francisco_Penaloza]

Oh you are using Mental Ray, I thought you use Scanline.

Well Mental Ray has some overwrite shaders too that will solve this problem. But as mentioned by Alfred, the options are in the material it self(see attached image)

When I get home I'll take a look where the mental ray shaders are, at the office we have Max 2016 only.