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Jason

Challenge: Sunburn!

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Steven, tell us what you did..

I edited my previous post so it seems like I posted first!

:P :P :P

Well then I guess you win! :lol:

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Awesome work guys, this stuff scares me. :blink:

It's clear to me that I have a loooot to learn about this little app called Houdini.

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Hey DaJuice,

Well, to be honest, here is where Houdini REALLY excels. Trying to do any of this in Maya or Lightwave, Mirai and Max would take some serious scripting. This is done in 10 or so SOPs in Houdini. Just a little bit of an open mind to all of it is all you need.

I am really excited that people find the Effect Challenges a good thing. It's all important to know how to cross-pollinate the different areas of Houdini. In the words of Side Effects themselves, they want people to not just use the traditional model/animate/render style of thinking - they want people to regard every aspect of the package a potential renderer of data and images. This is why they wrote VEX : to unite all contexts of Houdini. Maybe this'll create a nice new challenge.. something to do with rendering in other contexts.. hmmm - I'll mull it over...

B)

What sound does a Tapir make?

The Grand High Tapir.

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You know, Jason, I'd NEVER EVER imaging to look into the direction of Lambertian shader to solve a particular problem in your SOP! This is so neat! :)

Now I will have to start looking into other area and hopefully find some way to incorporate what I know into Houdini. (After gaining some experience, of course.) Now these are the kind of stuff my school doesn't teach. (Ok, Garman is the only exception in my school IMHO. :) )

Also, doing motion blur without the object moving (Velocity blur), I was already blown away by that one. :)

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speaking of fun velocity blur. You should try this.

With the comb SOP, you can specify an arbitrary attribute to comb. So try combing the V attribute, its pretty cool.

The only problem at the moment is that you can't visualise it yet without rendering. So what I did was comb the point normals and then rename those to velocity (attribute SOP) and rendered, and got all sorts of funky motion blur.

fun fun fun :)

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Hey Jason

Just went through your method for the sunburn, but my pointSOP which reads in the expression for baking light into the points - "dot(normailize...." doesn't evaluate.

I've gone over and over it, and i'm guessing i'm doing something wrong which i am simply missing. But just wondering if there may be a typo in the expression,( i don't notice anything but i'm no expert on expressions ), or if anybody else experienced this.

Thanks

Betty

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Guest Buzz
Hey Jason

Just went through your method for the sunburn, but my pointSOP which reads in the expression for baking light into the points - "dot(normailize...." doesn't evaluate.

I've gone over and over it, and i'm guessing i'm doing something wrong which i am simply missing. But just wondering if there may be a typo in the expression,( i don't notice anything but i'm no expert on expressions ), or if anybody else experienced this.

Thanks

Betty

change vector with vector3 ;)

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Thanks buzz!!!!

Well just finished it off and a great intro to the challenges. Great work Jason, really appreciate you giving us a peak into the power of Houdini, and making it look so simple!

Very much looking forward to more. Amazing how much i've picked up on in the last two weeks!

Betty

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ok, here goes nothing......

I just tried this as a solution....far from perfect, but

a ) it works :)

b ) it's interactive (on this machine at least)

err....but if I ever get hit by a london bus.....you're on your own :)

enjoy!

chlnge.2.zip

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argh!!!!

oops... I didn't realize we weren't supposed to post the "hips"...

so much for "speed" reading...

ok.......so no one takes a peak before Jason says it's ok ;)

kudos, steven!

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walkthru time.....

erm....ok upon reviewing Steven and Jason's reply, I pretty much did the same thing (save from using that handy Ray hit group, which made things a little more involved....)

the only difference is in self-shadowing, I discovered by accident a nice feature of the group SOP:

if you go to "group by normal" you'll find the option "backface from" which does exactly what it says! it gives you a quick way to separate the prims that are looking towards/away from a certain objects, in our case, the light source.....presto! got the main emitting surfaces from that!

Just when you think you know everything about *some* of the regular SOPs, they still find ways to surprise you! ....ain't that cool! :P

Cheers everyone!

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That excellent, Charles...er... Sirogi. It's great to see another approach like this..

Well done!

J.

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these challenges are a cool idea im going to do them all, I've already learnt a lot just reading them! B)

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Ahh man, nobody's replied to this for 3 years... talk about being late to the party. Oh well, 3 years ago I didn't even know what Houdini was, so better late than never:

http://brianrwalters.com/downloads/gooey.mov

(I must confess, I did have to read the hint about the Ray SOP to get the shadows... very clever Jason!)

More challenges!

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needed to revisit this thread for a little reminder of something...and I realized that an added fun thing would be to support spotlights...

so I used Jason's description and included support for a spotlight

anyone care to try before I post my hip?

here is a little flipbook of an animated cone angle

sunburn.zip

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needed to revisit this thread for a little reminder of something...and I realized that an added fun thing would be to support spotlights...

so I used Jason's description and included support for a spotlight

anyone care to try before I post my hip?

here is a little flipbook of an animated cone angle

yeah sure:

sop_light_flipbook.mov

+self shadow

+blurred shadows

:)

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I gave this challenge a try. I think it's pretty similar to Jason's solution but I used a vopsop to calculate the light falloff instead of the expressions. I had fun with this and am hoping to find time to do more of these old challenges and hopefully some of the new ones as well.

sunburn_v03.hipnc

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