Paul_ Posted January 8, 2018 Share Posted January 8, 2018 Hi there, With much help from the forums, I have discovered how to emit particles from an alembic line based on velocity. (see attached). My problem is that this solution uses nodes that are now obsolete or changed, (point, vopsop, group etc). Would anyone know how to simply rebuild this with the current houdini nodes? Any help is much appreciated. Paul PARTICLE_BIRTHRATE_FROM_VELOCITYv01.hipnc WOBBLE_LINEv01.abc Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) from what I can tell..you only have to change in group1 the expression to: @Cd.r>0.7 (instead of the old $CR) after that does it look right to you ? ps: I can't quite work work out what the purpose is of add1 and point1 (old), (are they superflous?) can someone explain ? Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
Paul_ Posted January 8, 2018 Author Share Posted January 8, 2018 Hi Noobini, thanks for the fast reply! Group seems to have been updated... If I add a new group node, the 'number' tab where the expression is does not seem to exist. Am I missing something? Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) it's now Group Expression (because we are going to use expression), they separated it... (I just retried your old group...seems to work fine with $CR...I'm going nuts...) Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 btw, in your VOP, i reckon after the fit1, it should go straight into fval1, the vectofloat1 is definitely superflous.. Quote Link to comment Share on other sites More sharing options...
Paul_ Posted January 8, 2018 Author Share Posted January 8, 2018 Thanks Noobini. I have found that the new group expression works, however, when I delete the old 'Group1' node, it breaks it. Also as vopsop is now obsolete, how do we replace? Thanks again for your help Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 your Impulse Birth Rate should now refer to: (coz we've ditched group1) point("../../groupexpression1",1,"Cd",0)*50 Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) for VOP add an Attribute VOP...inside should be same as before (but see the superflous note above) Having said all that, I'm still puzzled as to WHERE it breaks, I tried your orig file...seems to work fine for me... Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
Paul_ Posted January 8, 2018 Author Share Posted January 8, 2018 That's awesome thanks so much. Its working great. When I replace the old popnet with a new popnet however, the 'impulse birth rate' is no longer there. Is there a way to reveal this in the new popnet? Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) it should now be in your POP source, Birth tab, I think paste the expression into Impulse Activation ? Ok, here's where I'm struggling due to no experience...but here goes: 01) select your POP source, Source tab, set Emiision type to All Points, in Source Group, select point_source from drop downlist 02) Birth tab, paste point("../../groupexpression1",0,"Cd",0)*50 into Impulse Activation 03) set Const. Activation to 0 (do this with your fingers crossed that is) Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) something's not right, think I stuffed up the Impulse Activation.. I think step 01) above should use Points instead of All Points, this will enable more option in Birth tab Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
Paul_ Posted January 8, 2018 Author Share Posted January 8, 2018 Yes that seems to be working! I have added a value into impulse count and it seems to be working great! Thanks again Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) here's what I think it should be...(note groupexpression1 not group1) (your orig expression point("../../group1",1,"Cd",0)*50 is using point 1 instead of 0...I don't know why) Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
Paul_ Posted January 8, 2018 Author Share Posted January 8, 2018 Thanks Noobini, I cannot see any visual difference in the result between 1 and 0. They both seem to work well Quote Link to comment Share on other sites More sharing options...
Paul_ Posted January 8, 2018 Author Share Posted January 8, 2018 Hi Noobini, When the pop network is in the Geo node it all seems to work fine. If I wanted to have a separate AutoDOP network, would the expressions need to change? Quote Link to comment Share on other sites More sharing options...
Noobini Posted January 8, 2018 Share Posted January 8, 2018 (edited) prolly not but i'm not too confident on the path tho ie. the ../../ pretend you named your line object as emitter, then i'd say the expression would be point("/emitter/groupexpression1",0,"Cd",0)*50 ? or is that point("/obj/emitter/groupexpression1",0,"Cd",0)*50 ? dunno...clutchin' at straws... Edited January 8, 2018 by Noobini Quote Link to comment Share on other sites More sharing options...
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