Simply Maya User Community - Maya Tutorials

particle direction with animated characters

Razor Blade — Sat, 19 May 2012 01:01:37 GMT

Ever wanted to make a particle go in the direction your character is pointing and don't want to animate the emitter directly? Yeah, didn't think so..

In two of my small projects I wanted to create some muzzle flashes for guns and i hate hand animating everything so i wanted a solution to do this automatically for me.

What I did was I parented a directional emitter to a specific joint, namely the hand of the character and made it directional. You will have to do just a little tweaking to get the emitter to point straight but once its done that's all for that.

So once you've done, setup your emitter rate. Your emitter rate is how many particles per second you want to emit, so 30 will give you 1 particle per 1 frame. So given that, let's say that your weapon of choice does 600 rounds per minute. 600 rounds per minute / 60 minutes = 10 rounds per second / 30 frames per second = 1 particle every 3 frames.. see how that works out? So 10 is what you would put in for your emitter rate. This will serve as your bullet or round. You want to set your speed up correctly because this is what we'll use to setup and create our muzzle flash. Now even though your scene is set to cm, its actually...meters.

Now you can hit play, but regardless of what it looks like, we're not done because those particles aren't going to go in the direction you want to yet. Expressions is how we will achieve the second part, and this is the meat and potatoes of this whole plate of food...

This first set of MEL will grab the direction and velocity of your bullet and create your muzzle flash
This goes into the creation expression of the bullet emitter, we are creating our muzzle flash from this

Code:

//get the location of the barrel emitter with xform

//using tx will not work since you parent the emitter

//to the weapon, parenting the emitter to the weapon

//makes all translate in localspace 0



float $eLoc[3] = `xform -ws -q -t LH_LB_Emitter`;

float $eLocX = $eLoc[0];

float $eLocY = $eLoc[1];

float $eLocZ = $eLoc[2];



//assign the emit command to a string

string $emitCmd1 = ("emit -o LH_LB_MuzzleFlash \n");

string $emitCmd2 = ("emit -o LH_LB_MuzzleFlash \n");



//get a random count of how many particles for each command

//you want to emit

int $emitCount1 = rand(1500, 2500);



//the start position for each particle is at the

//location of the emitter in worldspace

for($i = 0; $i < $emitCount1; $i++)

{

        $emitCmd1 += "     -pos " + $eLocX + " " + $eLocY + " " + $eLocZ + "\n";

        $emitCmd2 += "     -pos " + $eLocX + " " + $eLocY + " " + $eLocZ + "\n";

}



//apply attribute velocity

$emitCmd1 += "     -at velocity\n";

$emitCmd2 += "     -at velocity\n";



//give each particle their initial velocity

//the sphrand function is used to give each a

//general velocity, to get a bigger muzzle flash

//adjust the rand(0, ##) higher 0 to whatever

//You will need to adjust the divmod on the sparkShape

//to get the desired muzzle flash effect, both go

//hand in hand



for($i = 0; $i < $emitCount1; $i++)

{

        vector $randVel1 = sphrand(rand(0, 50));

        vector $randVel2 = sphrand(rand(0, 15));

        float $ranVelX = $randVel1.x;

        float $ranVelY = $randVel1.y;

        float $ranVelZ = $randVel1.z;



        $emitCmd1 += "                    -vv " + $ranVelX + " " + $ranVelY + " " + $ranVelZ + "\n";

        $emitCmd2 += "                    -vv " + $randVel2.x + " " + $randVel2.y + " " + clamp(0, 30, $ranVelZ) + "\n";

}



//set a random lifespan for each particle

//adjust according to get the desired effect

$emitCmd1 += "     -at lifespanPP\n";

$emitCmd2 += "     -at lifespanPP\n";

for($i = 0; $i < $emitCount1; $i++)

{

        float $randls = rand(0, .025);



        $emitCmd1 += "                    -fv " + $randls + "\n";

        $emitCmd2 += "                    -fv " + $randls + "\n";

}

eval($emitCmd1);

eval($emitCmd2);

Notice in the above code, I have clamped the Z value in velocity. You can clamp one of the other 2 velocity values if you change the direction set on the emitter. Its going to look wierd but if you try it out it will make sense. To me, the YZ plane is the wall, but when I tried to clamp the Y in this instance, I didn't get the result I was looking for (amazingly) it took a little playing around to figure out which one to clamp.

For testing, lower the emit counter at the top to 150, 200
you'll also notice I have 2 emitCmd variables.. 1 is for the base of the muzzle flash and the other is for closer to the emitter, which is the clamped value.

So simply put, the above states, when we create our bullet particle, create the muzzle flash...

Once this has been created, now we need to shape our particles correctly...
This goes in the creation expression of the 2nd set of particles

Code:

vector $bulletVel = LH_LB_ParticlesShape.velocity;

vector $muzFlVel = LH_LB_MuzzleFlashShape.velocity;

int $partID = LH_LB_MuzzleFlashShape.particleId;

float $divMod;



float $angleBullet = angle($bulletVel, $muzFlVel);



//the divmod adjust the distance at which particles will travel in the direction of the bullets.

//higher numbers will make the muzzle flash shorter in distance.



if($partID%5 == 0)

{

        $divMod = rand(40, 80);

}

else

{

        $divMod = rand(20, 40);

}



//bullet velocity is multiplied by angelbullet/divmod so the muzzle flash doesn't travel the

//distance of the primary particle



float $newVelX = (($bulletVel.x * ($angleBullet / $divMod)) + $muzFlVel.x);

float $newVelY = (($bulletVel.y * ($angleBullet / $divMod)) + $muzFlVel.y);

float $newVelZ = (($bulletVel.z * ($angleBullet / $divMod)) + $muzFlVel.z);



//apply the new velocity direction to the muzzleflash



LH_LB_MuzzleFlashShape.velocity = <<$newVelX, $newVelY, $newVelZ>>;

the above code basically "Shapes" the muzzle flash for you. Find me the angle, and shape it...

If you want to go a step further and create particles for the smoke...
in your muzzle flash particle's Runtime before dynamics expression..

Code:

vector $MuzPos = LH_LB_MuzzleFlashShape.worldPosition;

int $partID = LH_LB_MuzzleFlashShape.particleId;



if($partID%5 == 0)

{

        //assign the emit command to a string

        string $emitCmd1 = ("emit -o MuzzleSmoke \n");

        

        //get a random count of how many particles for each command

        //you want to emit

        int $emitCount1 = rand(0, 2);

        

        //the start position for each particle is at the

        //location of the emitter in worldspace

        for($i = 0; $i < $emitCount1; $i++)

        {

                $emitCmd1 += "     -pos " + $MuzPos.x + " " + $MuzPos.y + " " + $MuzPos.z + "\n";

        }

        

        //apply attribute velocity

        $emitCmd1 += "     -at velocity\n";

        

        for($i = 0; $i < $emitCount1; $i++)

        {

                vector $randVel1 = sphrand(rand(1, 5));

                float $ranVelX = $randVel1.x;

                float $ranVelY = $randVel1.y;

                float $ranVelZ = $randVel1.z;

        

                $emitCmd1 += "                    -vv " + $ranVelX + " " + $ranVelY + " " + $ranVelZ + "\n";

        }

        

        $emitCmd1 += "     -at lifespanPP\n";

        for($i = 0; $i < $emitCount1; $i++)

        {

                float $randls = rand(0, .75);

        

                $emitCmd1 += "                    -fv " + $randls + "\n";

        }

        eval($emitCmd1);

}

Keep one thing in mind that if the scale of your characters and objects are bigger or shorter, you will have to modify all of the numbers above to fit...there's no magical number to this and I had this same expression for 2 different scenes, one scene had much larger characters. Its not easy, but the payoff is great

Hopeully this all makes sense! Let me know if you have questions!!

does anyone know how to render a movie texture?

saltedpopcorn — Fri, 18 May 2012 23:35:15 GMT

// Warning: (Mayatomr.Shader) : movie1: referenced texture file "/Users/saltedpopcorn/Desktop/saltedpopcorn maya project/scaryfilm.mov" doesn't exist, ignored

What am I doing wrong? The film shows when I move the slider in the timeline but once I batch render, I don't see it. :(

how to make a gray transparency sillouette

gilor7 — Fri, 18 May 2012 17:44:09 GMT

Hi, I am doing an architectural render. I am trying to make the 3d people just to look as a gray transparency sillouette. I have tried the surface shader and the map shader, but when i manipulate the transparency, in the render looks like a glass figure. Is there any other way to do this? or any other adjustment in the shader?

Simple nub problem

Jackratbone — Fri, 18 May 2012 10:40:55 GMT

Hey im new to using maya and im having a little issue thats driving me batty. While im using the create polygon tool to do exactly that i cannot see any of the vertices or edges of the polygon i am trying to create until the polygon is finnished. I would really like to be able to see the vertices as i make the polygon so that i can see the shape of the object i am making as i make it. They were showing last time i used the tool so i am assuming i have clicked something thats stopping it from showing up. any help would be apreciated.

caustics super bright

se7enhedd — Fri, 18 May 2012 09:57:00 GMT

hi,

I'm trying to render out a scene with a few bottles etc. in it - it's looking ok with global illumination and final gather, but the minute I switch on caustics it goes crazy. I read that you can't use directional lights (emitting photons) with caustics, so I switched off the photons on my main directional light and it fixed the problem but the resulting render had little 'zing'.
I switched photons on in the small point lights I have around the fg table and dialled down the global photons but I get these really burnt out brights. all the point lights have quadratic decay and are low intensity (tho I've been told that light intensity and photon volume/intensity are independent?)
It seems to be one material thats particularly prone to burn - you can see the very bright glass in the center, and also in the bg there's glasses with the same material glowing like mad. It's a miaX material, just a few standard glass presets blended together... all the other glasses have similar miaX blends applied. that said, the table is a standard anistropic, which still glows like mad even when I apply the initial lambert to it.

is there certain materials that're no-no's with caustics, or is there a particular limit to the total number of photons you should have in a scene? for example, if i have a point light or small spot that I'm using close to an object to create a few rim hi-lights ect. do I need to dial the number of photons down? there's quite a few lights around the fg so my thinking is that all the total number of photons is too great around that area. but of course, I don't know what I'm on about...:help:

Attached Images

caustic_forum.jpg (99.7 KB)

Simply maya Rain Tutorial

cellostree — Thu, 17 May 2012 13:25:59 GMT

Just downloaded simply maya tutorial on making rain, I think the tutorial is a bit incomplete as I have to set the particles speed to a lot more than 10 to get them to be falling at a faster pace, the air field is not working properly as well. I mean even if I set the direction of Z to 10 the particles continue falling vertically. Is there any settings that I need to change in order not to have to set the speed so high to make them work properly?

Simple planar UV Problem Grrr

djwaterman — Thu, 17 May 2012 13:00:30 GMT

I tried everything before posting this stupid question. I can't seem to do what should be a super simple UV map texture placement. Look at this...

That's my object with a surface to be UV'd on one side, and also that's the resulting UV view opened up.

So I snapshot that and took it into Photoshop and fitted my texture into it. See below...

...but as you see the texture is all spirally and twisted, also I can't even get that image to show up in the background of the UV texture editor.

Basically I don't understand what to do to get the imaged assigned to the UV map correctly, I generated a UV but so what, there's no slot in the material attributes that is asking for a UV map, I don't understand and no tutorial seems to cover this part.

I'm not unwrapping, I don't need to shift points around to fit the reference, my texture just needs to map directly onto the UV's. What am I missing? Please, I'm losing it.

Cartoon Chirstmas Scene

eneuman — Thu, 17 May 2012 05:50:26 GMT

Here is my first render. I am looking for advice and critique on how to make it better, especially on the shading, lighting, and rendering aspects. I am planning on adding a couch and a picture on the wall on the right side so it doesnt look so empty. this was completely inspired by Oasim from pixelophy.com, he gave me the idea, many techniques, and advice for it.
Hope you like it!
noted issues:
-carpet needs more texture
-too much shadow on teddy's face

http://s7.postimage.org/c3e08movt/render1.jpg

matching Camera Perspective

jrm522 — Wed, 16 May 2012 17:17:36 GMT

Hello all,

I've embarked on a little project which will eventually allow me to experiment with realflow. my only hurdle at the moment is my lack of understanding of perspective. I've made a maya scene (correct proportions modelled from an image)and i am trying to match a cg stationary camera to the scene. I thought this would be easy but I am really struggling to match a camera to the image. You will see from the attachment what I mean. This has been done successfully in CG before with a 50mm lens but I fail so far.

Any thoughts/approaches would be great!
Thanks J

Attached Images

screenGrab.png (347.7 KB)

I want a flickering light

bleepurchin — Wed, 16 May 2012 15:49:50 GMT

Hi guys,

I'm new to maya's expressions and I really don't understand scripting much at all generally.

I've been searching online for an expression to control the intensity of my point light and I found several.

I created a new expression on the intensity and copied the coding into the expression editor. I always get some kind of error telling me an 'attribute is not found or variable missing'.

Pointlight1.intensity=linstep(-1,1,noise(time))*0.2+1.5;

That is one script I inputed.... It uses noise as the randomness.... At least it's supposed to but fails to work in this instance... I don't get it!

What should I be typing that will work please!?

Oh, and if you have some suggestions, please don't assume I know to replace certain text or numbers with my own values because to some of us, it really isn't that obvious! ;)

Ps - my point light intensity is 2000 using quadratic interpretation.

Thanks!

Luke.

moving noise in animation

se7enhedd — Wed, 16 May 2012 11:33:14 GMT

I've produced a texture with various fractals and noise plugged into it. it looks fine in a still render, but when its used in an animation one of the noise layers seems to 'animate' (like tv static)
I know little about rendering/textures, but I think it may be because the noise is being re-generated in each frame; am I right in thinking this. And if so, how can I stop it?

thanks

Vray strange thing?

djwaterman — Wed, 16 May 2012 11:30:36 GMT

Okay, I'll try to describe it. Let's first imagine I have an object, and this object gets duplicated (mirrored) using 'duplicate special'.

(these could be chrome headlight rims for example, a situation where you would mirror the geometry.)

Now I apply a Vray mtl surface to both objects.

Now I render this simple set up and find that the duplicated object has a different look to the original.

And here's the funny part, if I reverse the normals on the duplicated object and then render, they will now both look correct.

Has anyone struck this anomaly?

It's got something to do with Vray materials, and duplicated mirrored geometry. If I just do a straight duplicate I will not get this problem, so it must have something to do with the flipped or reversed nature of the duplicated geometry.

Animating and constraints

snvn — Wed, 16 May 2012 08:35:31 GMT

I have a reverse foot setup that has been constrained to the foot joints and single ik chain in the leg (for a project...) Everything works fine until I try to set a keyframe. For some reason, after setting the key the leg/foot no longer follows the reverse foot setup, it just stays in the same place but all the constraints are still visible in the hierarchy...

Download exceed 150 times

yuquanzhou — Wed, 16 May 2012 04:56:36 GMT

Hi, there. When I go to download page, I get a message says I exceeds download 150 times limit today, could someone tell me what happened or anything I can do to fix that?

Problem with VRaylightmtl

eneuman — Wed, 16 May 2012 03:55:26 GMT

As you can see, I attached a ramp to the color, but i still get all white, here is a screenshot of my settings. thanks!

http://postimage.org/image/ffwsnlthv/full/

I am aiming for exactly this but in blue

Diablo 3

MamoruK — Tue, 15 May 2012 22:00:16 GMT

so who got it today and what do you think so far from the maybe collective hour you played it?

Alternative to Grouping Objects?

AlienHook — Tue, 15 May 2012 17:09:03 GMT

Recently, when I need to re-size multiple objects which need to retain their relative distance from each other, I've been grouping the objects. However, I noticed this really screws up my Outliner and keeps me from organizing my scene.

For example, I was building a barn, when I decided that I wanted to make the building bigger in proportion to the objects inside it. If I just selcted the walls/ceiling and scaled them up, they wouldn't be scaled as a group.

Is there another way to scale multiple objects simultaneously? Should I be combining the objects then separating them afterwards?