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mamurphy
12-06-2003, 07:16 PM
I'm having an issue with shadows cast by an object with an alpha map in the transparency channel of the suface editor.

To make it simple I created two flat polygons: One for the floor to receive the shadow and the object to cast it.

With shadow map on it cast a solid shadow (No alpha transparency) onto the floor.

With ray trace shadows it didn't cast anything-(yes I had ray trace shadows on.)

I don't know if this can be done, but I believe it can.

I'm posting a couple of pics to show what I mean..the one of the left is the shadow map and the one on the right is the ray trace.

I'll also post my settings....

I'm sure someone out there can help me figure this out..I checked the manual, the message boards and Inside LW 7 and can't find the answer.

Thanks

mamurphy
12-06-2003, 07:16 PM
Here are my settings

WizCraker
12-06-2003, 07:48 PM
Use a clip map instead of a transparency map to get it give you the correct shadows.

mamurphy
12-06-2003, 08:01 PM
GREAT!

It works with shadow map but not ray trace shadow (Using a spot light)

Is that right, or do I need to be aware of another setting for raytrace shadows?

Thanks again!!!!!:D :D :D

SplineGod
12-06-2003, 08:37 PM
When using clip maps make sure to turn off texture anti aliasing or you may get funky results. So if you need smoother edges to clip maps make them higher rez.

mamurphy
12-06-2003, 10:13 PM
Thanks Larry,

BTW, is there a particular ratio of pixels to LW units to use or keep in mind when building clip maps/texture maps?

for example, if a cube is 1 meter square and will be output to NTSC resolution, what would be the best size/resolution for clean clips and close ups of textures?


(Larry, I'm trying to make up my mind to buy your training courses. I've worked through your fabulous freebies and learned a tremendous amount. Look forward to a purchase of your Intro to LW soon!)

ps-My avatar is the result of expanding on your freebie subpatch head modeling tutorial!!:D

SplineGod
12-07-2003, 12:17 AM
Originally posted by mamurphy
Thanks Larry,

BTW, is there a particular ratio of pixels to LW units to use or keep in mind when building clip maps/texture maps?

for example, if a cube is 1 meter square and will be output to NTSC resolution, what would be the best size/resolution for clean clips and close ups of textures?


(Larry, I'm trying to make up my mind to buy your training courses. I've worked through your fabulous freebies and learned a tremendous amount. Look forward to a purchase of your Intro to LW soon!)

ps-My avatar is the result of expanding on your freebie subpatch head modeling tutorial!!:D

Hey Thank you! :)
Theres no particular aspect unless you need them for background images or plates then you need to worry about that. For a texture map it doesnt matter because you can resize them. What does matter is the resolution if you plan to get pretty close.

Thats cool the you were able to expand upon the freebies to do your avatar. :)

As far as my training courses go, the freebies I have are scratching the surface when it comes to the rest of the courses and the online support I provide. The face modeling is just the first 20 minutes or so of the Character modeling Module which is about 15 hrs by itself. The full course is over 60 hours. If you really are interested drop me an email and lets see what we can do. You can also check out my support forum HERE (http://www.learningstop.com/cgi-bin/dcforum/dcboard.cgi) . Login as guest, password guest.
If you take a look youll see that I do provide good support and students really are learning valuable information. :)

toby
12-07-2003, 03:31 PM
One point that needs to be made clear is that Shadow Maps do not see transparency (as in the surface channel - they do of course work with clip map type 'transparency'), you will get the same opaque shadow regardless of trans. level.

If your raytrace shadows are not showing up then you need to either flip the polys or make them double sided - one-sided polys only cast shadows in one direction.

tburbage
12-13-2003, 04:51 PM
If you have a non-solid object like a plane of one or more polys which you want to use a transparency or clip map on (to represent a grid or something)

-- and you want a ray traced light to do the shadow casting

-- either double to polygons of the plane and flip the copy or, easier, set the surface attribute of the plane's surface to "double sided"

There have to be normals facing the object receiving the shadows for ray traced shadows to show up.

As already pointed out, a shadow mapped spotlight will also work in this situation. That doesn't help for your other types of lights, though...

The only way I know of outside of manipulating the shadow in post to get a diffuse shadow would be spinning lights.

Ezequiel
12-13-2003, 10:59 PM
Please forgive my ignorance level but would any of you tell me what's the difference (technically) between alpha and clip map?

Ezequiel

toby
12-13-2003, 11:08 PM
Alpha channel is used to mask out parts of a 2D image or footage. Clip map is a black&white image that's used to mask out parts of geometry from being rendered in a 3D program.

Ezequiel
12-13-2003, 11:11 PM
Tanks a lot Toby ;)
Now I get the idea. Rather important difference I would say

Tanks again:)
Ezequiel

toby
12-13-2003, 11:15 PM
nice to have someone from BA!

didn't it get wiped out by the Arachnids? :D

Ezequiel
12-13-2003, 11:28 PM
I'm sorry I'm afraid I didn't understand the thingy about the arachnids, I would like to know a lot more of english. It's a cool language, anyway thanx for the comment.
I'm glad that I can share common interests and knowledge with people like you in this forum. It's very cool.

Does Wipe mean the same as bite?:p :p :p

Ezequiel

toby
12-13-2003, 11:35 PM
sorry, I was refering to the Starship Troopers movie, bad joke, I know - :(

'wiped out' is like 'destroyed quickly and completely'

Ezequiel
12-13-2003, 11:48 PM
Ok, now I supose I get it. :) :)
In Starship troopers there is a scene where BA is wiped out or refered to as wiped out by some kind of arachnid things, right?
Not yet... :p :p :p

Anyway that wasn't so bad toby :p :p :p

Heyy you must be a long time lightwaver now..

I forgot to ask then, how is that you do a CLIP map in LW.
I think that was intended to be my question the first time.
I tried but I didn't get the shadows right...

toby
12-14-2003, 12:02 AM
Directly under the Render tab in the Object Properties panel there is a button for 'Clip Map', you apply it like a texture.

And if you like Sci-Fi at all, go rent Starship Troopers immediately. It was made in '97 but the effects are still awesome.

Ezequiel
12-14-2003, 12:22 AM
You bet I'll do that!!!:)

OK thanks a lot again. Very clear explanation.
I think I'll go to get some sleep now so the arachnids cath me sleeping and leave me there because they would think that I'm dead and they don't like dead meat. :p :p :p I hope...:(


It's 4.15 AM in BA
Are you from the Americas, Europes, Africas or Asias? Anyway Internet is wonderfull.

If you want give a try to my modeling thread about the Coke Bottle named COKE BOTTLE TROUBLE as I am getting mad trying to figure out a solution to that mesh.

Although you may already know....
Remember mesh is one letter away from mess...;)

Thanks again,
Ezequiel

toby
12-14-2003, 12:56 AM
hmm... it's only 11:30 here in California - BA must be further east than I thought.

Ezequiel
12-14-2003, 11:31 AM
California is a looong waayyyy from hooome, like I said before, the net is way more than cooooolllll:cool: :cool:

Ezequiel