[Sidefx-houdini-list] Bridge of Cards

Antoine Durr antoine at floqfx.com
Mon Mar 17 14:01:05 EDT 2008


Hmm, I tried it, and it worked just fine.  Are you sure you're  
looking at the primitive attributes and not the point attributes in  
the geometry spreadsheet?

-- Antoine

On Mar 17, 2008, at 10:36 AM, pingo van der brinkloev wrote:

> 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
>>> _______________________________________________
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>>> 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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> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

-- Antoine

Floq FX Inc.
10659 Cranks Rd.
Culver City, CA 90230
310/430-2473







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