[Sidefx-houdini-list] Bridge of Cards

Antoine Durr antoine at floqfx.com
Mon Mar 17 11:03:07 EDT 2008


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
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>>>>>
>>>>> _______________________________________________
>>>>> Sidefx-houdini-list mailing list
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>>>>>
>>>>> _______________________________________________
>>>>> Sidefx-houdini-list mailing list
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>>>>
>>>> -- Antoine
>>>>
>>>> Floq FX Inc.
>>>> 10659 Cranks Rd.
>>>> Culver City, CA 90230
>>>> 310/430-2473
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>>
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>>>
>>> -- 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 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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-- Antoine

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







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