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gopper0815

Colorattribut will not read by ramp

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Hello,
i follow actually a tutorial from Rohan Dalvi “Desserttutorial”. In this he use a old pointnode that in Houdini 18 not longer extist. In this node he created a coloratribut to white. Then he set a colornode and choose Ramp from attribute. The attribute is Cd. With this he can change the scale of a sphere. I tried this with other nodes, but it seems that the colorramp not work. I used a colornode to create a cd-attribute and set it to white. Then i used a second colornode, as in the tutorial and choose also rampt from attribute. in the following copystamp node i set the value for the variable to @Cd.r, but the scale of the spheres a all the same. Whne i look in the spreadsheet, all the colorattributs in the second colornode are at 1. But some of them must have a different value, because of the ramp. s you can see in the screenshot, at the second colornode (that one with the ramp), all colorattributes are at 1

colornode1.PNG

colornode2.PNG

nodes.PNG

spread.PNG

stamp.PNG

Edited by gopper0815

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The RampFromAttribute mode in the color node uses an attribute to map it onto the ramp. The attribute should be normalized, what means it should go from 0-1. e.g. you can create an float attribute called "pscale" with an attributeRandomize sop. Then you have a attribute and then you can use this attribute as input for the ramp. In the color node you could then put "pscale" into the attribute name and the color should appear correctly. In your current setup you set a color with value (1,1,1) as input for the ramp and since the value 1 is the most right value of the ramp, the result is.... well 1. Attached is a simple scene where you can see how an attribute can be used as ramp input : colorfromattr.hiplc

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Thank you for this explanation. This makes me understanding this a little bit more. But i have the problem that i need a constant scale from 0 to one, without random. In the tutorial he took this old attribut node and created the this with the $bby command. But this dont´t work anymore in Houdini. Unfortunately he doesn´t explain, what this $bby do, so i don´t know, how i can setup a similar attribute.

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