Dear Sir :
Ask A somple question a . I wish I will not bother you so much.
Does any shader in SHOP is similer with the dent texture in older version ?
I know I should create in VOP by myself .But you know I am not very good at in VOP .So does any shader in shop is similer with Dent ,I want to map in Geometry to look like fire .

Thank you very much .


Best Regards,

Winnie

I don't know what the old Dent was like but have you tried the VEX Fractal Dent displacement shader SHOP?

For fire, there's always the Fire VOP but I've never tried it before.

Dear Edward :
I can use it in the Shade displacement and I have no ideas to use in shader surface . How to use that ?
Would you pls explain clearly ?

Thanks .

Winnie

Winnie,

go into VOP's and hit tab laying down a VEX Surface shader, then select the shader (you may want to rename it) and hit enter, thus stepping into the VEX builder.
Here you see an Output VOP, lay down a Fire VOP (by hitting tab and typing fire), now connect the fire color output to the Cf input of the Output VOP and connect the Opacity output from the fire to the Of input of your Output VOP.

This done you can right click on your Output VOP and choose ‘Create New Shop’, now when you go into Shop's you will see your fire surface shader there with the same name you gave it (i.e. fire1).

One thing though you will not have any paramteres in Shop's to adjust in order to get them you can MMB on the input parameters of your fire and choose ‘Create Parameter’ now these will be available in Shop's.

Perhaps it would be a good idea to go through the various tutorials on VOP's they are very helpful and should get you started with the basics.

I hope this helps.

Andre

Funny- I was just playing with this last night! I also found that it worked best to plop down a Rest Position VOP and pipe that into the “P” input of the Fire VOP. This made the VEX shaded display result match with the mantra result. I am not sure why they didn't match without that… I guess the shader space is not necessarily the same.

Also, be sure to pipe out “Offset” as a parameter so that you can animate the fire (I just put $F/10 or something like that in the Y “Offset” channel of the SHOP) and do this for the other parameters you may want to tweak in your SHOP.

But what is really cool is the VEX Shaded mode works really great for this!! I made a NURB grid in XY facing the camera, gave it UV texture coordinates, slapped the Fire SHOP I just made onto it and turn on VEX Shading and got a pretty darn good representation of the fire. I animated the offset like I mentioned above and did a Flipbook of 100 frames. This looked fantastic and allowed me to really see the timing and size/scale/detail of my fire in less than a minute rather than having to render out a test animation. It was almost like having OpenGL hardware rendering, but not quite as fast.

I feel that it was good enough that if scaled down it could be composited into a scene without rendering, although I forgot to check to see if it had Alpha. Sometimes flipbooks (like Maya's don't preserve Alpha.

This is utterly fantastic!!! I wish I had this ability to do quick preview flipbooks for animated procedural shaders for every movie I worked on before now…

(By the way, this topic probably should have been presented in the Technical Forum since it is more specific and technical than General, and there is more traffic there, meaning you are more likely to get a response.)

-Craig

This made the VEX shaded display result match with the mantra result. I am not sure why they didn't match without that…

hey craig,

i could be wrong on this one, but i think the reason that it didnt' match up before was because your vex shading position did not match up with your uv coordinates. the manual explains why the rest position was matching it up. and because im assuming you used the default settings on the vop, it was doing the texture conversion:

From manual:
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This operator contains a subnetwork that checks if the geometry attribute “rest” is bound and, if so, uses it as the rest position for shading. If no such binding exists, it converts the incoming position (P) to the specified space.
The “Texture” option takes a position in world space and converts it to shader space.
__________________________


where this will screw you up in the future is if you need to bring in uv coordinates to your obj (in the case the grid). throw down a uv project after your shader sop and move it all around your grid. you will notice is is not changing or updating anything in your render. now try putting down a shading layer parameter vop in place of the rest vop and plug that in to your P input of the fire. now if you go back to your grid and throw down a uv project, your shader will behave accordingly with your uv project unlike before. unforunately, the draw back to this is that it will not update in your vex shaded display. only after rendered. so you lose that.

what i just end up doing is going to the viewport, hit tab, type render, select the render op and draw my selection box in the viewport to see it update. this is really great when in the vex desktop. i can be working on my vops, with seeing my viewport up in the right corner having a selection box of it being rendered and updated as im working. plus i can be moving around my uv's, editing my shader, and seeing it render and update all at once. it's extremely fast and powerful this way.

hth,
dave

Well, UV is UV and doesn't have anything to do with the position in space. A shader using UV doesn't need rest position or anything piped in- it already sticks to the surface. In your example it seems like you are converting UV to position coordinates which the shader seems to be using.

So it seems that the shader was written as a 3d procedural that is using position for it's calculations and not UV coordinates from the surface. But why would the position P that the VEX shader see be different from the position Mantra sees? VEX Shaded mode just calculates the shader that you hook up to the object at each CV or vertex. It should be the same calculations as a Mantra render, just different resolutions and quality. Putting the Rest VOP down is intended to keep the texture stuck to the surface, so it doesn't “swim” through it when animated. I can't think of any reason why VEX Shaded Mode is in a different space than the Mantra render.

Anyway, I am having PC problems on my Houdini PC right now so I can't test it out.

Oh well. It just seemed weird and unexpected.

-Craig

Dear All :
Thanks for replay . I got the fire finally .
Thanks again and again.


Winnie