Soft Shadows ?

[Simon Edmondson]

]It seems to be the season to ask questions about shadows ( !)...

 

I am trying to be more systematic in my approach and, after losing a lot of time due to operator error. I finally got a lighting set up in a choreography that I liked. The shadows were an interesting shape and lead the eye into the picture.

 

As part od the new approach I re read the section on lighting in the old V8 manual and in the new Technical reference book and thought I'd try it with more than one way cast for the shadows. The results were a big disappointment and I don't know if its me or a problem ?

 

The two included files show what I mean.

 

Example 1 is using one ray cast per light ( four lights used ).

The shadows are clearly defined and the other side of the street evenly lit.

 

Example 10 is using 10 rays cast per light ( otherwise no change in number of lights or their position and orientation )

The shadows are softer but they now occupy nearly all the space and the opposite side of the street is in deep shadow ???

 

Toon render was used for both on a Imac 3:03 running snow Leopard on V13 of AM ( I haven't tried it on V15 yet ) . Does anyone know whats happening ?

 

Thank you in advance.

regards

simon

[robcat2075]

With 1 ray, shadows are automatically diminished as they stretch away from the object

 

With > 1 ray they do not diminish but can have more accurate penumbras in their shadows.

 

 

many light settings may play into your results, such as width, falloff, "darkness" and position and it's hard to judge those from the two images.

[Simon Edmondson]

many light settings may play into your results, such as width, falloff, "darkness" and position and it's hard to judge those from the two images.

 

 

Hello again Rob.

 

Thank you for your reply.

 

The four lights are 'suns' and I think, all the settings except the number of Rays are the default values.

Just checked.

Width and falloff are 150cm and the darkness is the default 80 %. The position of the lights does not change from one to the other, the only change is to the number of rays cast ?

 

regards

simon

[Darkwing]

I generally change my suns to klieg lights as you'll then have better options for shadows and the shadows will fall on objects and block out the light, whereas with sun lights, it'll light whatever side is facing the light, no matter what object is in front of it

[robcat2075]

. The position of the lights does not change from one to the other, the only change is to the number of rays cast ?

 

 

I'm sure there's a simple reason, but without knowing how everything is arranged in the chor and what's in front of what and what's not in front of what... it's hard to diagnose.

[Simon Edmondson]

I generally change my suns to klieg lights as you'll then have better options for shadows and the shadows will fall on objects and block out the light, whereas with sun lights, it'll light whatever side is facing the light, no matter what object is in front of it

 

 

Thank you for that I shall try it later. I'm just trying to find a setup to give me a general effect for the street scene I'm working on.

regards

simon

[Simon Edmondson]

. The position of the lights does not change from one to the other, the only change is to the number of rays cast ?

 

 

I'm sure there's a simple reason, but without knowing how everything is arranged in the chor and what's in front of what and what's not in front of what... it's hard to diagnose.

 

Rob

 

Is there anything I can do to get the info you need, such as a screen shot of the top view of the chor /If so ca you let me know and I will post that ?

 

 

regards

simon

 

ps

I'm more familiar with PC's so not sure howto do a screen grab on a Mac...

[Darkwing]

CMD+SHIFT+3 will screen grab and save it to your desktop.

 

The best way for anyone to help you is for you to upload and post the project to the forum, then masters like Rob can go through it and do the incredible work they do

[Simon Edmondson]

CMD+SHIFT+3 will screen grab and save it to your desktop.

 

The best way for anyone to help you is for you to upload and post the project to the forum, then masters like Rob can go through it and do the incredible work they do

 

 

Thank you for the info re Mac screen grab. I shall have a go tomorrow ( UK time ).

Thanks also for the suggestion re uploading. I'll have a look at that tomorrow too. I didn't want to impose on peoples good will more than I have already....

regards

simon

[R Reynolds]

It appears from your example scene that you're trying to simulate sunlight which is basically a single, extremely distant area light source. I have been able to satisfy my needs with a 208 ft. diameter klieg with the properties shown in the attachment, located almost 3.5 miles from the models. I also use ambiance occlusion to fill in the shadows with sky light but that may not be the look you're after.

[John Bigboote]

Sweet! Can't wait to try that out Rodger! Good trick, Looks like a fast render too...

[Simon Edmondson]

It appears from your example scene that you're trying to simulate sunlight which is basically a single, extremely distant area light source. I have been able to satisfy my needs with a 208 ft. diameter klieg with the properties shown in the attachment, located almost 3.5 miles from the models. I also use ambiance occlusion to fill in the shadows with sky light but that may not be the look you're after.

 

Rodger

 

Thank you for that. I shall try that too.

I'm going to post the project if I can to see if theres a fault in that ( it wouldn't be the first time I've eerred... !

regards

simon

[Simon Edmondson]

Consolidated_Street_Projectr.zipConsolidated_Street_Projectr.zipThe best way for anyone to help you is for you to upload and post the project to the forum, then masters like Rob can go through it and do the incredible work they do

 

I'm still a bit vague about attaching files so, I hope this works.

I have uploaded a zipped version of the project using a slightly modified model setup ( I've removed all the decals to keep it easy ). I checked before uploading and the same problem persists ,

 

adding more than one ray cast causes a form of black out in some aeas...

 

Thanks in advance for any help

regards

simon

[Simon Edmondson]

Apologies for double file posting.

Sorry !

simon

[Gerry]

I think you can delete one by going into your controls>manage attachments, and delete one of them.

[Simon Edmondson]

It appears from your example scene that you're trying to simulate sunlight which is basically a single, extremely distant area light source. I have been able to satisfy my needs with a 208 ft. diameter klieg with the properties shown in the attachment, located almost 3.5 miles from the models. I also use ambiance occlusion to fill in the shadows with sky light but that may not be the look you're after.

 

 

 

Rodger

 

You are right about the bright sunshine

I tried the method you suggested but, I work in cm and, when I converted to the imperial units you suggested I had to convert and ( with my capacity for Maths ) didn't do that good a job. I will remember the technique for next time though !

regards

simon

[robcat2075]

I took a quick look.

 

One way to diagnose these things is to turn all the lights' Active properties OFF and then turn them on individually to see what they are doing.

 

Keylight (4) seems to be causing the unwanted shadow. Turn that one OFF and see if the result is more like what you wanted.

 

I'd have to look at it longer to figure out WHY it is doing that since it is a "sun" light and is aimed the same as the other sun lights. But turning off #4 solves the problem I think. If not, post a new picture and say what is still not right.

 

Sun lights cast parallel rays over an infinitely wide area so their position shouldn't matter much, only their angle. You really should only need one sun light rather than 4 aimed in the same direction.

[Simon Edmondson]

Robert

 

Thank you very much for that I will try it tomorrow.

I have a test render going through as I type to test something else. I am learning ( very slowly ) to be more systematic so a sole light suource on a different scale to rodgers suggestion, is tomorrows task.

I took note of your recommendation in another post about the book on digital lighting (?) and keenly await its delivery.

regards

simon

[Simon Edmondson]

Sun lights cast parallel rays over an infinitely wide area so their position shouldn't matter much, only their angle. You really should only need one sun light rather than 4 aimed in the same direction.

 

Rob

 

I followed your advice and deleted all but one light and then proceeded from there. Finally, I realised what the problem was.

 

With a single ray cast the shadow shape was sharply defined, as you suggested.

With multiple rays the penumbra becomes more pronounced and takes up a larger area... ?

I think that was the problem.

I include two renders,

One with single ray the other with 5 rays cast. Both from a single source with no other differences.

 

The nost notable difference in the result is the size of the shdow aea (?)

I think the reason I was getting thetrouble was because I was adusting the lights to get the shape I wanted with a single ray and, when I switched to multiples did not know to adjust for penumbra size.

SO, the overall darkening was caused by the multiple penumbras spreading over the area, making it look dark ?

 

Inexperience strikes again...

Thank you kindly for your time.

regards

simon