[Sidefx-houdini-list] Bridge of Cards

pingo van der brinkloev houdinilist at comxnet.dk
Mon Mar 17 13:36:13 EDT 2008


Hey Antoine.
It all makes sense (points are points, etc) and It certainly should  
work the way you describe, but it just doesn't. not with `$PR` either.
A shame you don't have a houdini in front of you cause I would really  
like to have someone confirm this.

I am using a standard grid with nothing changed. It's got 81  
Primitives. (100 points)

On the attribCreate with Class as Primitive, Type as String and $PR in  
String the attributes dissapear from the details view

very odd.

Cheers!

pingo


On 17/03/2008, at 18.03, Antoine Durr wrote:

> If you're making an attribute of class 'point', then no, you don't
> have access to $PR, as $PR is the *primitive* number (which you don't
> "know" about when looping through the points list).  Likewise, you
> can use $PT in the points context, but not the primitive context.
> The only example below that might work is the class=prim,
> type=string, string=$PR example.  Mouse-middle on the SOP above the
> attribcreate: how many primitives do you have?  If you have a NURBs
> patch, then yeah, I would expect only one primitive, number zero.  If
> you have 100 polys, then $PR *should* go from 0 to 99.  You may need
> to backtick the $PR (`$PR`) when making a string (don't have Houdini
> in front of me, so I can't test).
>
> -- Antoine
>
> On Mar 17, 2008, at 9:21 AM, pingo van der brinkloev wrote:
>
>> Hey Antoine. I might be doing something wrong, but I can't get the
>> AttribCreate to use the $PR in he string
>>
>> this works
>>
>> I make a grid
>> connect it to an AttribCreate
>> 	Class = Point
>> 	Type = String
>> 	.
>> 	.
>> 	.
>> 	String = $PT
>>
>> If I look in the details view I can see my attribute1 changing  
>> numbers
>> along with the point number.
>>
>> but...
>>
>> Changing things in the attribcreate doesn't work as I would expect...
>>
>> 	Class = Primitive
>> 	Type = String
>> 	.
>> 	.
>> 	.
>> 	String = $PT
>>
>> Attributes dissapear
>>
>> 	Class = Primitive
>> 	Type = String
>> 	.
>> 	.
>> 	.
>> 	String = $PR
>>
>> Attributes dissapear
>>
>> 	Class = Points
>> 	Type = String
>> 	.
>> 	.
>> 	.
>> 	String = $PR
>>
>> Attributes reapear but are all = 0 (zero)
>>
>> Is this supposed to happen??
>>
>> thanks for your time!
>>
>> pingo
>>
>> On 17/03/2008, at 16.03, Antoine Durr wrote:
>>
>>>
>>> On Mar 17, 2008, at 7:40 AM, pingo van der brinkloev wrote:
>>>
>>>> Hello Antoine. I've been following this thread with great interest.
>>>> Could this technique be used to create a grid with an (adjacent
>>>> numbered) image on each face?
>>>>
>>>> what would be the shortest steps to produce that?
>>>
>>> Sure, that's easy!  Just an attribcreate SOP again using $PR in an
>>> expression (but again, you first need to find out what the parameter
>>> is on the *shader* that will take the unique named map (often called
>>> 'map', but not always).
>>>
>>> -- Antoine
>>>
>>>>
>>>> regards
>>>>
>>>> pingo
>>>>
>>>> On 16/03/2008, at 11.12, Antoine Durr wrote:
>>>>
>>>>> Wow, 87,000 polygons for a single card?  That'll slow you down!  I
>>>>> would expect a playing card to be in the hundreds of polys at  
>>>>> most,
>>>>> not tens of thousands!   I'd start out by temporarily replacing  
>>>>> the
>>>>> card geometry with a simple rectangle -- one polygon (a.k.a.
>>>>> primitive), then see if the $PR in attribcreate works.
>>>>>
>>>>> Yeah, with multiple primitives per card, you'll get each  
>>>>> subsequent
>>>>> card on adjacent primitives -- definitely not what you want.
>>>>> You'll
>>>>> need to isolate the face of the card into one SOP,  and everything
>>>>> else as another SOP.
>>>>>
>>>>> The randomization is in the expression you use to set the map
>>>>> attribute.  I gave a simple example -- card.$PR.jpg.  What you're
>>>>> more likely to need is
>>>>>
>>>>> card.`int(rand($PR)*$NPR)`.jpg
>>>>>
>>>>> though I prefer to use fit() to have deliberate control over the
>>>>> output range (1 to $NPR in this case)
>>>>>
>>>>> card.`int(fit(rand($PR), 0, 1, 1, $NPR))`.jpg
>>>>>
>>>>> Again, check here with the geometry spreadsheet that your
>>>>> assignments
>>>>> worked out as planned.  Then it's a matter of copying both the  
>>>>> face
>>>>> polys and the non-face polys to the points (via the copy SOP, as I
>>>>> assume you're doing).
>>>>>
>>>>> Actually, now that I think about it, you probably want to apply  
>>>>> the
>>>>> attribcreate to the *points* onto which you will copy the cards,
>>>>> first.  Still separate and do two copies, one for the faces, one
>>>>> for
>>>>> everything else.  On the copy SOP operation with the faces, you  
>>>>> can
>>>>> have the single face polygon inherit the attributes from the
>>>>> points.
>>>>>
>>>>> -- Antoine
>>>>>
>>>>>
>>>>> On Mar 16, 2008, at 2:33 AM, Chandra Maharzan wrote:
>>>>>
>>>>>> I have copied over 1 card. It just say 87000 Primitives when I
>>>>>> middle mouse
>>>>>> click on the attribcreate SOP. It also says 1 Primitive Attribute
>>>>>> and card
>>>>>> -> card.01.jpg. So I am guessing it is only taking 1 primitive to
>>>>>> replicate
>>>>>
>>>>>> just one texture for all the cards. Isn't there a way to assign
>>>>>> each of the
>>>>>> copied primitives to take random textures? I am a newbie and I am
>>>>>> not so
>>>>>> sure of what you are trying to explain to me.
>>>>>>
>>>>>> Thanks and let me know if there is a way to figure it out.
>>>>>>
>>>>>> Chandra
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: sidefx-houdini-list-bounces at sidefx.com
>>>>>> [mailto:sidefx-houdini-list-bounces at sidefx.com] On Behalf Of
>>>>>> Antoine Durr
>>>>>> Sent: Sunday, March 16, 2008 2:37 PM
>>>>>> To: sidefx-houdini-list at sidefx.com
>>>>>> Subject: Re: [Sidefx-houdini-list] Bridge of Cards
>>>>>>
>>>>>> The attribute type has to match the type of the parameter of the
>>>>>> shader.  Typically, the 'map' parameter is a *string* parameter.
>>>>>> In
>>>>>> the attribcreate, you'll proabably use something like card. 
>>>>>> $PR.jpg
>>>>>> (i.e. one map per primitive).  Whether the attribcreate is before
>>>>>> or
>>>>>> after the material SOP doesn't matter so much, as both of them
>>>>>> just
>>>>>> add *attributes* to the geometry.  Use mouse-middle on the SOP or
>>>>>> the
>>>>>> geometry spreadsheet to see what attribs are ultimately there
>>>>>> (especially of the SOP that is used to render).
>>>>>>
>>>>>> -- Antoine
>>>>>>
>>>>>>
>>>>>> On Mar 16, 2008, at 1:08 AM, Chandra Maharzan wrote:
>>>>>>
>>>>>>> This is quite unclear to me. I created the attribcreate SOP
>>>>>>> infront
>>>>>>> of the
>>>>>>> material SOP and gave the name card (as the cards are named  
>>>>>>> card.
>>>>>>> 01.jpg,
>>>>>>> etc) and then type=float size 3 or 2.. but it didn't work
>>>>>>> properly.
>>>>>>> I have
>>>>>>> the Texture map set to .../card.$F2.jpg
>>>>>>>
>>>>>>> What am I doing wrong here or missing?
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Chandra
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: sidefx-houdini-list-bounces at sidefx.com
>>>>>>> [mailto:sidefx-houdini-list-bounces at sidefx.com] On Behalf Of
>>>>>>> Antoine Durr
>>>>>>> Sent: Saturday, March 15, 2008 2:29 AM
>>>>>>> To: sidefx-houdini-list at sidefx.com
>>>>>>> Subject: Re: [Sidefx-houdini-list] Bridge of Cards
>>>>>>>
>>>>>>> Look at the shader that you're using.  Is there a field for map
>>>>>>> name?  If so, make an attribute on your geometry with the same
>>>>>>> name
>>>>>>> and type (using attribcreate SOP), set each name randomly (have
>>>>>>> names
>>>>>>> like card.0001.jpg, card.0002.jpg, and so on to make it easier).
>>>>>>> Now
>>>>>>> rerender, and each card should be  unique.
>>>>>>>
>>>>>>> -- Antoine
>>>>>>>
>>>>>>> On Mar 14, 2008, at 1:01 PM, Chandra Maharzan wrote:
>>>>>>>
>>>>>>>> How can we assign random textures ? That might be a good
>>>>>>>> trick so
>>>>>>>> we can get
>>>>>>>> all the cards.. :)
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: sidefx-houdini-list-bounces at sidefx.com
>>>>>>>> [mailto:sidefx-houdini-list-bounces at sidefx.com] On Behalf Of
>>>>>>>> Jerry
>>>>>>>> Corda-Stanley
>>>>>>>> Sent: Saturday, March 15, 2008 1:24 AM
>>>>>>>> To: sidefx-houdini-list at sidefx.com
>>>>>>>> Subject: Re: [Sidefx-houdini-list] Bridge of Cards
>>>>>>>>
>>>>>>>> That's some pack of cards. All aces!
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> ----- "Chandra Maharzan" <chandra at digital.com.np> wrote:
>>>>>>>>> Hi Guys,
>>>>>>>>>
>>>>>>>>> By the way, if you were wondering what I was upto and sending
>>>>>>>>> all
>>>>>>>>> those
>>>>>>>>> newbie questions, here is what I made. :)
>>>>>>>>>
>>>>>>>>>
>>>>>>>> http://bp0.blogger.com/_ZoZUTKmj098/R9rCJ6QlbiI/AAAAAAAAADM/
>>>>>>>> Y8mervJCHMo/s160
>>>>>>>>> 0-h/bridge-full.jpg
>>>>>>>>>
>>>>>>>>> Hope you like it. (My blog - http://
>>>>>>>>> learninghoudini.blogspot.com/)
>>>>>>>>>
>>>>>>>>> Thank you all for your prompt replies and I am looking forward
>>>>>>>>> to
>>>>>>>>> learning
>>>>>>>>> more of Houdini in coming days.
>>>>>>>>>
>>>>>>>>> Regards,
>>>>>>>>> Chandra
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> Sidefx-houdini-list mailing list
>>>>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-
>>>>>>>>> list
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Sidefx-houdini-list mailing list
>>>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-
>>>>>>>> list
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Sidefx-houdini-list mailing list
>>>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-
>>>>>>>> list
>>>>>>>
>>>>>>> -- Antoine
>>>>>>>
>>>>>>> Floq FX Inc.
>>>>>>> 10659 Cranks Rd.
>>>>>>> Culver City, CA 90230
>>>>>>> 310/430-2473
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Sidefx-houdini-list mailing list
>>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini- 
>>>>>>> list
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Sidefx-houdini-list mailing list
>>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini- 
>>>>>>> list
>>>>>>
>>>>>> -- Antoine
>>>>>>
>>>>>> Floq FX Inc.
>>>>>> 10659 Cranks Rd.
>>>>>> Culver City, CA 90230
>>>>>> 310/430-2473
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> Sidefx-houdini-list mailing list
>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>>>>
>>>>>> _______________________________________________
>>>>>> Sidefx-houdini-list mailing list
>>>>>> Sidefx-houdini-list at sidefx.com
>>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>>>
>>>>> -- Antoine
>>>>>
>>>>> Floq FX Inc.
>>>>> 10659 Cranks Rd.
>>>>> Culver City, CA 90230
>>>>> 310/430-2473
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Sidefx-houdini-list mailing list
>>>>> Sidefx-houdini-list at sidefx.com
>>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>> _______________________________________________
>>>> Sidefx-houdini-list mailing list
>>>> Sidefx-houdini-list at sidefx.com
>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>>
>>> -- Antoine
>>>
>>> Floq FX Inc.
>>> 10659 Cranks Rd.
>>> Culver City, CA 90230
>>> 310/430-2473
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Sidefx-houdini-list mailing list
>>> Sidefx-houdini-list at sidefx.com
>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
> -- Antoine
>
> Floq FX Inc.
> 10659 Cranks Rd.
> Culver City, CA 90230
> 310/430-2473
>
>
>
>
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list



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