rd1010 Posted September 5, 2009 Share Posted September 5, 2009 I'm wondering if anyone can offer a hint on this as I'm trying to figure out how to create a transparency map within a VEX builder shader SOP... I've been fumbling around with it a bit but I'm fairly new to using the VEX builder.. I gather that it would be a texture passing through a composite SOP but can't seem to figure out how to input the variable for it to "subtract" which makes the texture map into a transparency map... don't know really where to start as I'm not seeing the subtract option anywhere on the composite SOP. Thanks for any advice Quote Link to comment Share on other sites More sharing options...
vfxkid Posted September 5, 2009 Share Posted September 5, 2009 i think you have to connect any vector value to the Of (suface opacity), which is in the output variable node. Quote Link to comment Share on other sites More sharing options...
rd1010 Posted September 5, 2009 Author Share Posted September 5, 2009 (edited) Thanks for the response... that sounds right, I will try that.. EDIT: I am playing around with this but still don't get exactly how to do it.. probably since I am still pretty new to VEX building.. if anyone has any further specifics I would greatly appreciate your input.. I will post a file here later on once I play around with it more to ask more specifically what I am doing wrong. Edited September 5, 2009 by rd1010 Quote Link to comment Share on other sites More sharing options...
rd1010 Posted September 5, 2009 Author Share Posted September 5, 2009 (edited) Hoping you can clear this up as I'm confused on this.. should I be outputting the vector node to the composite SOP or the final output SOP? Also, I have gotten the parameter attached to the vector SOP but its only showing one line on the material parameters within the SHOP which is just three boxes with values: 0 0 0 (like you'd see for map coordinates or something).. are there other SOPs I need to attach to the vector SOP to get the parameters to allow me to choose the compositing values (subtract, add, etc)? Thanks for any help on this as this will be very helpful to me once I get it figured out EDIT: I think maybe I need to input a string? I recall seeing the string when looking at the type properties of a "vex layered surface" shader.. I'll try this later on when I get back home. Edited September 5, 2009 by rd1010 Quote Link to comment Share on other sites More sharing options...
vfxkid Posted September 5, 2009 Share Posted September 5, 2009 i am a pretty newbie at vex to but based on your question i think what you need to do is from the texture that you crated you have to use that and figure out what areas you want to be transparent and then plug that as a vector in surface op. Think of it kinda as a alpha channel the vector node. so if you use your texture info all the dark areas should be transparent and the color area should be grey so semi transparent and white should be clear. Quote Link to comment Share on other sites More sharing options...
rd1010 Posted September 5, 2009 Author Share Posted September 5, 2009 (edited) Thanks... that makes sense.. EDIT: Ok I think I have wrapped my head around this.. I'm going to start over with a new vex surface and try it the way I think will make it work based off what you said and I'll post here if with the results for future reference if I can get it to work Edited September 5, 2009 by rd1010 Quote Link to comment Share on other sites More sharing options...
rd1010 Posted September 6, 2009 Author Share Posted September 6, 2009 (edited) I made some slight progress but am still completely perplexed by this... I would greatly appreciate if anyone can take a look at the files below and offer any guidance.. this is a picture of my vex network, and then a render... this is a grid directly in front of the two spheres, it has a decal texture map on it which is the blue circle you can see in the render (the pic with the black background) which then only has an alpha channel around it.. yet for some reason where the alpha channel should be it is showing this green tint over the balls.. the transparency is working to some extent as you can see but I have no idea why this green tint is showing up. The blue circle with white background image is the decal map I am using.. I have tried it both as a .pic file and as .png.. I attached it as a .png... on a web browser the alpha channel would be the white area.. so that is the area that is showing as green over the spheres in the render. (lastly is the houdini file) I greatly appreciate any direction on this.. could be that I am just missing something very simple since I'm new to VEX building. VEX five.hipnc Edited September 6, 2009 by rd1010 Quote Link to comment Share on other sites More sharing options...
rd1010 Posted September 6, 2009 Author Share Posted September 6, 2009 (edited) EDIT: it posted my previous post twice.. removed this one. Edited September 6, 2009 by rd1010 Quote Link to comment Share on other sites More sharing options...
sam.h Posted September 6, 2009 Share Posted September 6, 2009 (edited) If Opacity is 0 the colour will be *added* to any shading behind it. You need to mult the colour by the alpha so the white doesn't get added to the shading behind it. Your blue circle is premultiplied over white, so you will get a white edge. The colour of the texture should be solid blue (un-premultiplied) or a blue circle over black (premultiplied). Hope this makes sense ... Edited September 6, 2009 by sam.h Quote Link to comment Share on other sites More sharing options...
rd1010 Posted September 6, 2009 Author Share Posted September 6, 2009 Thanks.. I think i just saw something like this in one of the posts on the shader forum so I think I'm heading in the right direction now and will try using a multiplier Quote Link to comment Share on other sites More sharing options...
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