I've been having this extremely aggravating bug for quite a while now. And it is seemingly random, giving me trouble pinpointing what is causing the issue. Right now I'm using Houdini 12.1.125, and I'm doing a project with particles (a school of fish).

I was previously having no issues rendering, and then suddenly when I add in a Light with “enable spot light” checked, I start running into the issue of mantra not rendering a sequence past frame 1. It just hangs and MPlay never opens.

I deleted and remade mantra nodes several times. I tried using the lowest sample settings. I tried closing and re-opening Houdini. I tried changing the light type from “point” to “disk” which worked initially, but then when I added my projection map (for dappled lighting) it hung again on frame 1. The projection map is a targa sequence that worked at school on Houdini 12.0, and is imported like: $HIP/textures/dappledlight_$F5.tga. It looks fine as a single render in the render view, but when I try to render a frame range? Nothing.

Just to make sure, I created a new file with a grid, spotlight, and the projection map on the light and rendered frame range, and it worked perfectly fine, MPlay opening and everything.

Any ideas? I guess my general question would be why does mantra do this and what can I do to prevent it? It also happened in my previous project, to the extent where I had to render it on my school's renderfarm.

Thanks in advance!

Post up a stripped down scene file showing the problem and by stripped down I mean as basic scene file as possible. With your Houdini build and system specs. Without extra information it makes it very difficult to say what is causing issues.

Thanks for the reply circusmonkey. I attached my hipnc file, though the fish templates and textures will break because they are being referenced from my $HIP directory, which is not included. All of the mesh and particles and whatnot are living in the “fish_underneath” geo, and everything else is named self-explanatory.

You are going to call me crazy because before I saved this out cleaned up, I did a “render frame range” and mantra suddenly decided to work! But still, feel free to look around and if you find anything that may be causing the random render hanging please let me know! I'm still a noob, just learned Houdini in January.

Thanks!

Build Version: 12.1.125 (I think? I am not sure how to find build version. It is a full-featured Apprentice HD license if that helps)

PC Specs:
CPU: intel i7 3770K 3.50 GHz
GPU: Nvidia Geforce GTX 660
RAM: 16GB
OS: Win7 64-bit Ultimate

cant look at the file, but sometimes mantra does that for me too. when it happens make sure you look at the terminal to see if it is telling you anything. if its not throwing any errors sometimes manually opening mplay and selecting listen for renders fixes it.

Zdimaria: Thanks, that's a great tip! I didn't even realize I could access MPlay from the toolbar, I'll definitely try that next time it acts up.

Nicole Rager
You are going to call me crazy because before I saved this out cleaned up, I did a “render frame range” and mantra suddenly decided to work! But still, feel free to look around and if you find anything that may be causing the random render hanging please let me know! I'm still a noob, just learned Houdini in January.

Hi,
I am glad it works now, stripping your scene down to debug and find the problem is part and parcel of doing 3d. Sending a file with missing links is not of much use. You need to make the problem occur with as basic assets as possible. Doing this will also help you better understand where the problem might be.

Rob

Yes, thank you circusmonkey! I am still a novice in 3D, started learning 3D about a year ago so I am still working on improving my workflow and problem solving techniques. I really want to become a power user, so I will remember your advice for next time I encounter an issue! Thanks again