Fireplace - how do you block light from going through?

[Eric2575]

I moved this from http://www.hash.com/forums/index.php?showtopic=17591&st=40 because it started to take on a life of it's own. Here is the latest render of this WIP.

 

I read a post a while back that mentioned double patches between a light source and an object you want shielded from the light. I did this on the inside of the fireplace, but it still seems to let the light through. Can someone refresh my memory on how to block light to the inside of the chimmney?

 

Comments and critique welcome.

[AniMattor]

Light coming from where?

 

It looks like you have non-shadow-casting lights. If that is the case I don't think you can block the light. But you could put some diffuse maps inside the chimney to make it darker than the rest of the room.

 

Hard to tell w/out knowing more of your scene.

 

(BTW, very good rocks. Modeled or textured?)

 

cheers,

 

matt

[KenH]

I think it was that you had to "double up " the splines to get it to cas a shadow. Might be something to do with the normal direction though....

 

The bricks on the inside od the chimney look like an image because the bricks curl round the corner.

[DanCBradbury]

I think your lights aren't casting shadows, because no where in the scen can i see any sort of defined shadow anywhere. You may want to check and see if the light shadow darkness is up to 100%.

 

Very cool fireplace. Did you use the new displacement tool for that?

[Eric2575]

You guys are all right. I assumed the shadow setting was on , but it wasn't. Once applied, the shadow worked fine, even inside the fireplace with my double walls.

 

Yes, the rocks were done with a displacement map in V.13Alpha. After rendering with shadows, however, I noticed a booboo (tha'd be a mistake) about how I made the map. Never having made a map before, I added shadows to the bottom of every rock on the color map, thinking it would give a better depth illusion. In retrospect, this was not necessary, since the displacement worked so well. The contours created actually added shadows from the light above. These shadows and the shadows I drew on the color map gave too much depth on the bottom side of the rock, making it seem as if they were drooping down. This has really been a good learning experience for me.

 

Ken, you have a good eye. I'll fix that. Geez, can't even get away with a little cheat once in a while

 

I'll play around with some lighting and post one more shot later. Time to learn some particle emitter stuff. Now if I could just learn how to simulate a fire like Colin, I'd be set.

 

Eric

[Eric2575]

In this test, I put two light sources on the side of the fireplace simulating candles. The light from the candle sources is going throught the fireplace and the double walled shield inside. Wow, is there any way to keep light from going through models?

[luckbat]

Are you using raytraced shadows or z-buffered?

[oakchas]

That's moonlight, reflecting off the walls of the chimney and flue. Sheesh! A:M is testing the new smart render feature.

 

It extrapolates as follows:

 

one light in scene, otherwise dark, fieplace =Must be evening, moon outside.

 

This is all for the "make me a blockbuster" button that will be added in V15.

[KenH]

The light just seems to be on the very back wall in the chimney area. Is that the same mesh that the candle is on?

 

BTW It's probably going to be daytime in this set, so no candles are needed, but it would be nice to get right. Also, do the candle holders not seem a bit small?

[Eric2575]

Ken, the light is actually on the back wall of the shield model inside the fireplace. The shield model is completely separate from the fireplace and from the wall model. Good thought though. You are right about the set lighting being daytime too, but as you said it would be nice to get it right - not going to expend much energy on this. Scale wasn't a big consideration at this point either, Mr. Eagleeye, er, I mean Ken

 

Luckbat, I believe I am using 2 raytraced shadows. Would that make a difference?

[DanCBradbury]

You didnt know displacement maps casted their own shadows? That's one of the coolest features about displacement maps ⌐_⌐

 

anyways, it does seem like there is a light comming through your chiminey. You only need one patch to stop light, so you dont have to build double thick walls to make sure your chimney is sealed. Make sure your light setting has both 100% darkness shadows and 2 ray casts: you do this to break up banding when you render with multipasses.

 

looks good eric

[Eric2575]

Ok, did some more experiments. Dan, you were right about the shadows. The default setting is 80% which for whatever reason lets the light through the shield patches. When I set the shadows to 100% the inside of the fireplace was nice and black.

 

The issue with the newly created lights not turning on in the renders was worked around by shutting of AM and restarting. This is an issue with AM V.13Alpha and is not really an issue for users with any other version of AM. As I am writing this, a render of the last test is running. Will post when done.

[Eric2575]

Call me Hippe-Dee-Hop, cause I jump from one issue to the next. The render looks great, except...you tell me.

 

Settings:

 

Shadows - on

Darkness - 100%

Rays cast - 2

Intensity - 80%

Multipass - 16x

Soften - on

 

Ok, you've already seen the problem. The areas the problems appear in are five point patches. Any ideas what's causing them?

 

Were almost there guys, let's get this last little challenge out of the way.

[KenH]

You're a pioneer Eric. Sounds like that 80% thing might be a bug...

 

I assume you're sure the FPP's are flipped the right way round. If they are, send it into Hash.

[Eric2575]

Ok, the first renders, the one's that had the shadows turend off for the keylight, did not have the artifacts in the 5 point patches. The next renders with shadows "on" made the artifacts appear. To make sure, I played around with shadow intensity and rays cast, with no effect - the artifacts were still there in the renders. Only when I turned off "cast shadows" did the artifacts disappear.

 

Gonna make sure I got this all straight and can reproduce it, then off to reports it goes. Geez, and the render with shadows was looking so promising.

 

Ken, FPP's? Do you mean Normals? If so, yes, they are all facing out.

 

If anyone has any suggestions as to why this may be happening, I'm all ears. I'll wait for 24 hours for suggestions to try and rectify this before I'll make a report.

 

Update: I started a new prj file and made a few patches including a 5 pointer. Next I added the same displacement map as the fireplace and rendered with only the keylight turned on without shadows. That one rendered as expected, no problems. Next I turned shadows on, expecting artifacts in the 5 point region - no artifacts??? Hmmmm, so now I'm thinking there may be another problem with my fireplace model. So now I import the fireplace model into the same modeling window as my test patches and render side by side with shadows on. Guess what? The fireplace model shows artifacts and the test patches do not. Ergo, the fireplace model has more problems. Now to figure out what they are.

[luckbat]

You're a pioneer Eric. Sounds like that 80% thing might be a bug...

Ken, the 80% default is an attempt to simulate, crudely, the "spill" from a given light source--since in the real world nothing casts a pure black shadow. If you have an object in the chor with a light shining on it using the default settings, you'll get an 80% black shadow, meaning that 20% of the light is passing right through the object.

 

Whether the 80% setting should be the default is debatable, but it's definitely not a bug.

[DanCBradbury]

Yeah... i wish martin would set the default light darkness to 100%... that always gives me a headache when i'm trying to do radiosity or testing some new lighting feature and cant figure out why my shadows are all screwy @_@

 

Anywyas, the 5-point patch problem is widely known at this point. The Sully model recently produced in A:M and rendered with AO show the same artifacts that you have on your fireplace. One person said that even though the problem is a known bug that you should post an error report anyways to set the priority with the hash crew.

 

Looking much better now Eric.

[luckbat]

Yeah... i wish martin would set the default light darkness to 100%... that always gives me a headache when i'm trying to do radiosity or testing some new lighting feature and cant figure out why my shadows are all screwy

Understood, but I know you know how to substitute your own default choreography.

[DanCBradbury]

lol you have a good memory. Yes i know how to create a default chor. but that doenst help me when i need a bagillion different lights in a scene XP oh well... i guess i'll just keep chaging the values for each light. lol

[luckbat]

Just create one light the way you want it, and then drag a bajillion instances of it into the Chor. You can always override a light instance's individual settings if you need to, but otherwise you'll be able to update all bajillion of them every time you update the original light.

[Eric2575]

I did some more experiments.

 

Putting a displacement map on a 5 point patch itself is not the problem, at least not that I have found. The artifacts in my model seem to be caused when I try to flatten the mesh, to get the displacement map to wrap smoothly around the corners. If I just apply the decal to the front of the fireplace, the 5 point patches render fine. Once I create an action to flatten the edges and sides, the 5 pointers seem to act up.

 

Btw, let's stay on topic please.

[Eric2575]

After several more experiments, I decided to recreate the basic fireplace from scratch. Keeping in mind basic , clean splinemanship, I came out with a model that does not display the anomalies in the 5 point patch region with 2 rays cast and 100% shadows. Having done that, it is obvious that the problem was one of my making and not one inherent to AM. Glad I did not report this before exhausting all the possibilites myself. Martin, hats off to you again for a fine product.

 

I'll post a more complete finished render later. Thanks to everyone again for hanging in there with me and helping out.

 

Eric

[DanCBradbury]

Well you see, the anomolies you showed above are a problem. They shouldnt have happend unless the 5-point patch was concave, which has always resulted in anomolies; however, this problem is happening with all 5-point patches regardless if they're concave or not, so it is a serious issue that i hope will die very soon... please kill it mr. hash... kill it good

[Eric2575]

Dan:

 

I'm not sure if we are talking about the same thing or not, because as I stated in my previous post, the new fireplace model I made from scratch does not exhibit the anomalies, although I put the same 5 point patches in the same location with the same general shape.

 

I didn't want to post another pic until I got a nice scene set up, but just to show you the flawless 5 point patch with 2 rays cast and shadows at 100%...