Candle Rendering and Volcano Advice

[timfagan]

I'm a beginner and creating a few simple sims to get me going. I'm currently making a simple candle but running into a few problems. Any advice would be great!

 

The scene is below, note I added a spot light just as a light reference.

 

One problem I'm having is that the top of the candle is cut off. The volume box for the pyro sim is growing, but not enough. I think in the pyro_sim node there's the resize_container node, should one of the bounding variables be linked dynamically to another variable, like the max height of the temperature field or something? 

 

 

I seem to be getting different rendered images depending on whether I'm using the on screen rendering window, or the different file outputs. For example the jpeg is significantly darker than the exr output. See the attached images...(left to right - on screen render, exr converted to jpeg, jpeg)

 

I'm using this video as a bit of a reference:

http://www.sidefx.com/index.php?option=com_content&task=view&id=1124&Itemid=295

 

 

I also created this basic volcano eruption earlier, the smoke isn't quite right and it kinda looks like a scale model. If anyone has any tips on making this or the candle look better that would be great! I've attached both files if anyone wants to check them out.

 

https://youtu.be/hOzwE4TU6q8

Candle_simple_05.hipnc

Volcano_10.hipnc

[jrockstad]

With regard to your images being lighter or darker depending on file format, it should be noted that Houdini is set up by default for a linear workflow. The best practice is to always render to a linear format such as EXR which you then apply the proper color space to in your compositor, at which point you can convert to any image format you desire. In After Effects, go to your Project Settings and look under the Color Settings section. Tick the Linearize Working Space checkbox then set your bit depth and working space (this will usually be sRGB unless you've specified differently in Houdini). You can find more information on the use of linear workflow in Houdini here:

 

http://www.sidefx.com/docs/houdini14.0/render/linear

[timfagan]

Thanks for the info John, I've haven't used After Effects before but I'll look into it. I definitely need to look into all this stuff more, I know people use Nuke too, but I'm not even sure what all these programs do exactly...

 

I just realized that I can import the exr files back into the compositor of Houdini. One of the problems I had was I couldn't actually look at the exr files without converting them to jpg or something first. Maybe this could help too.

[jrockstad]

You can think of After Effects and Nuke as being similar to Photoshop but primarily intended to be used with image sequences and video files rather than still images. They are used to color correct, mask, layer, and manipulate all your footage, 3D renders and other graphic elements in various ways to bring everything together for the final output. Houdini's compositing context is quite powerful in its own right and I encourage you to become familiar with it, but you will definitely want to add a proper compositing application to your workflow if you intend on doing more 3D work in the future. Be on the lookout for the free non-commercial edition of Nuke that's coming out soon.

[timfagan]

That's great I'll definitely check that out.