Houdini Render #7 - FIGHT!
- Sammy Lyu
- May 24
- 3 min read
13/05/2025 - 24/05/2025
First of all, I decided from to add a "Go back" button to all my posts, mainly because it was bothering me that I couldn't go back to the previous page without clicking back on my browser, you're welcome. Anyways, this post is quite a special one because I started when I didn't have a fully complete render to show, and for the past month I went through multiple iterations, drafts and camera angles. Although the scene itself didn't take long, it was the changes in simulation, cameras, and re-renders that took the most time. Strap in, the "key points" section this time is quite populated. PROJECT FILE:
Here's what I got in the end:
This was one of the first "full CG" scenes I rendered out. I had done some grading in Nuke and I did notice after rendering that the pillar doesn't fully touch the ground, so that's something to watch out for next time. KEY POINTS FROM THIS PROJECT: ATTRIBUTE / POINT VOPs
You can use an ATTRIBUTE INTERPOLATE sop to copy animation onto a point that you have frozen with time nodes like timeshift. This is because 90& of the time, ""point"-based effects are done on one frame, then animated later, it is not recommended to create an effect over moving points. (Although I did do a FLIP fluid sim over a moving emitter).
In the ATTRIBUTE / POINT VOP, you can use the "ramp" parameter, which is the same as the "ramp" function in VEX to change values like COLOUR (Cd) or intensity, by age and life.
When using FIT RAMP in the ATTRIBUTE / POINT VOP, you can also INVERT the range to have something start from 1 to 0 rather than the opposite.
PARTICLES / POPSIM
The CURVE U attribute adds NUMBERS to the points on a line, so for example, if you wanted to select a line at a certain points, you can use CURVE U to label that particular point with a number and reference that specific number.
The IMPULSE and CONSTANT activation differ in how it emit particles, impulse emits new particles every frame, while constant emits a set number of particles each second. So depending on how you scatter your points, as surface points or volumes, you should choose to use either impulse or constant accordingly.
In a POPSIM, you can put in the "object" window POP* to include the popobject you would like to select for render without other stuff like COLLISIONS and GROUNDPLANES.
You can use the POINT JITTER node to jitter points instead if you are not using the "points from volume" sop which already has jitter built-in.
When dealing with PARTICLE TRAILS, you can disable the "REAP PARTICLES" option to not have particles die off and use BLAST to delete the particles when they gain the "dead" attribute instead. This is because "reap particles" will negate the effect of the trail SOP.
TIMESHIFT
When using the TIME SHIFT sop, we are able to CLAMP frames according to when our simulations or animations start to avoid ERRORS on frames where the simulation has not started.
RBD SIMS
You can use the BULLET WORLD SCALE to change the way the simulation views the scale of the scene and as a result calculate the physics of the scene different. Good for when a scene scale is too small which causes tiny values to miscalculate.
RENDER FLAGS
You can CTRL + CLICK a node to enable it's render flag, this means that no matter where your blue view flag is, the node with the render flag will always be the point where the renderer will look to render out the final output in that particular geometry SOP.
Here is the FLIPBOOK where I drafted the scene before lighting and final rendering:
And that concludes last month's work!
