Mark Elendt


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Houdini Rendering & De-noising

Recent Forum Posts

Mantra startup time + PDG - [was Mantra geometry preparation] March 18, 2019, 10:56 a.m.

sure - it's the startup and initial setup of mantra. It occurs on Linux, windows and mac os. Do we have a solution for this slowness?
Depending on your studio's setup, mantra's startup time can be affected by engine mode. What times do you get when you run:
% time mantra -e none < /dev/null
% time mantra -e basic < /dev/null
% time mantra -e full < /dev/null
On my machine, the startup time difference is 0.5s vs. 0.9s. You can also control this using the

VEX structs & arrays of structs, lack of documentation Feb. 14, 2019, 8:57 p.m.

1) Wrangles are a bit of a strange beast. The wrangle code is actually pre-processed and used to generate a nested function which is called. I think we should try to fix the process so that structs could be declared in the nested function. It's likely a short-coming in the compiler.

If you dive into the wrangle, you should be able to view the generated raw VEX code on the enclosed node.

2) If you provide a default initializer for the edges array, it seems to be more acceptable
struct VG_MST {
VG_MSTEdge edges[] = {};
int _result[];
int maxID;
The compiler should probably not require that initializer though.

2b) I found a bug in the compiler than complains about the result declaration. It should be fixed in an upcoming build.

3) I wasn't able to reproduce your error (I assume the emoticon was a semicolon ; followed by a close brace )

4) The following is valid C++ too
    const int foo[] = { 1, 2, 3 };
int const foo[] = { 1, 2, 3 };
const int *foo = function();
But yeah, VEX is a bit loose with declarations.

Render view way faster(30x) than render to disk when timeline seeking after first render on trivial animation. Nov. 9, 2018, 8:48 a.m.

Paolo Oliverio
On windows, I once found that I could speed up the render startup significantly when running as admin.
thanks, I have tested it and I get 18 sec in Mplay with both standard and admin.

A 17 second start up time is outrageous and shouldn't be happening.
a) When you turn on verbosity in the render, what does the timing report?
b) Do you get the same behaviour if you render directly to disk files (i.e. render from the ROP)?
c) How long does it take for Houdini itself to start up?
d) What happens if you set the engine mode on mantra to “none”?

To me, this almost sounds like there's some kind of timeout happening, possibly with license checks? Or maybe loading a lot of different plugins?

This post ( from a long time ago seems that they solved the problem with a DNS lookup issue.