halion Posted June 25, 2004 Share Posted June 25, 2004 I've got this sop network and a pop network but I can't figure out how to connect them correctly. When I connect the pop merge to the merge all my objects turn black. How can I connect it without that happening? Heres a picture of the network Quote Link to comment Share on other sites More sharing options...
Lukich Posted June 25, 2004 Share Posted June 25, 2004 hey, halion! it is a bizzare thing, i reconstructed your network and yes, it does turn black if you connect the pop to the merge. However, it renders perfectly fine, but if you want to avoid that altogether, add another merge sop and merge the product of your first merge with the pop. did the trick for me. good luck! Quote Link to comment Share on other sites More sharing options...
halion Posted June 25, 2004 Author Share Posted June 25, 2004 Do you mean add another merge to the merge I already have? I tried that and it was still black. Quote Link to comment Share on other sites More sharing options...
Lukich Posted June 25, 2004 Share Posted June 25, 2004 yes, when i created another merge sop, i plugged in the outputs of merge sop 1 and pop sop into it and the color remained white. Quote Link to comment Share on other sites More sharing options...
stevenong Posted June 26, 2004 Share Posted June 26, 2004 Hi there, If you connect geometry with the Normal attribute into a Merge SOP, other connected geometry will turn black. The alternative is to append a facet SOP to compute Normals or delete all Normal attribute from any geometry before merging them. Cheers! steven Quote Link to comment Share on other sites More sharing options...
halion Posted June 26, 2004 Author Share Posted June 26, 2004 Thanks for the help guys. I got it to work with the double merge sop. The thing is I had to connect the popnet first then the first merge. Now I'm wondering how do you delete the normal attribute? Quote Link to comment Share on other sites More sharing options...
Mcronin Posted June 26, 2004 Share Posted June 26, 2004 It'll work with a single merge SOP if you merge the pop in first. Point normals are the problem. The surface normals are fine, which is why it renders properly. Facet doesn't seem to help after the merge either. As near as I can recon, and I'm by no means an expert.... The merge SOP basicly merges all this stuff into one object, right? When doing so it reorders all the points. It works fine when you give it the objects, but if you follow the objects with a mess of loose points, it's like the merge SOP doesn't understand where one surface ends and the next starts and doesn't know how to set up the normals properly, so all your objects are shaded black in the viewport. If you give it the popnet first, the merge SOP seems to have no problem working out the proper point order and everything works fine. As for deleting normals... I wasn't aware that was even possible. I always though a normal was one of those fundamental things that every point and primitive *must* have in order to be drawn. Is it really possible to delete them? Quote Link to comment Share on other sites More sharing options...
halion Posted June 26, 2004 Author Share Posted June 26, 2004 Crap I should've tried putting the popnet in first then the objects into the first mode after I found out thats how it worked in the second merge. Thanks for clearing me up with the merge sops it makes sense about how it works. Quote Link to comment Share on other sites More sharing options...
edward Posted June 26, 2004 Share Posted June 26, 2004 Well, normals are the pointer vector attribute N. So to delete this attribute, there's 2 ways off the top of my head: - Append a Point SOP and change it from Keep Normal to No Normal, or - Append a Attribute SOP and add N to Delete Attributes in the Point page Point normals are indeed needed for OpenGL rendering but if the N attribute does not exist, Houdini will just compute them on the fly for OpenGL using the averaged primitive normals. Quote Link to comment Share on other sites More sharing options...
sibarrick Posted June 27, 2004 Share Posted June 27, 2004 This seems to catch someone out nearly every day. I think it would be well worth the merge sop having an option to delete all point normals, and/or recalculate point normals, and/or create normals for inputs without them Quote Link to comment Share on other sites More sharing options...
Jason Posted June 27, 2004 Share Posted June 27, 2004 I'd agree; let the Merge SOP optionally (and by default) compute missing normals. Quote Link to comment Share on other sites More sharing options...
edward Posted June 27, 2004 Share Posted June 27, 2004 It's never supposed to delete attributes. I think it just subsitutes in missing values with the default of the first input. Quote Link to comment Share on other sites More sharing options...
old school Posted June 28, 2004 Share Posted June 28, 2004 I agree with Jason in that the merge SOP should properly build normals for all other inputs once it detects normals on any of the inputs. This behaviour shoud be able to be turned off though. It would be even nicer if the merge SOP gave you a yellow warning flag whenever it detects missing attributes on any of the inputs. It should also have the yellow flag if the merge builds any normals for one or more inputs indicating that it would be good to build normals for all inputs. I really don't want the merge to build normals for me in the long run. If I remove the merge SOP at a later date on some geometry that it was building normals for or switch the merge SOP in and out of a chain in an asset and I was depending on them, it will take time to figure that out and is potentially more confusing. Quote Link to comment Share on other sites More sharing options...
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