Cinema 4D and fluid/liquid sim production workflow


#1

Hi everyone.

As I begin to consider including fluids and liquids into my work, I thought I’d start a thread here to gather opinions and advice for what methods work best in a production workflow, especially in a one man freelance situation. I have not settled on a software solution yet, as there are pros and cons to each software choice.

The one issue that appears to be a caveat to some of the software options is this: How does a small shop effectively manage to get fluids and liquids rendered for big projects with tight deadlines and limited budgets? In order to do any kind of work requiring long render times, a render farm of some sort is usually necessary. From the research I’ve done, some fluids options work well with a render farm that is using NET render. And other fluids software? I’m not so sure.

I will go through the available options, and maybe there are options I am unaware of that others are welcome to add. Please correct me if my assumptions are incorrect in any of my thoughts below.
(This post is more directed towards liquids–not so much gaseous fluids)

Realflow
The most obvious choice and the gold standard. The cost can be prohibitive ($3995 USD) unless the project budget justifies. I’ve heard many complain of issues when trying to render with NET. (ie NET has trouble seeing the .bin files?) making realflow perhaps not the best choice when under a deadline where a farm is needed. I have heard that as a workaround, some artists will render the fluids separately on a local box and comp the results into the rest of the scene. I can see this working in some cases, but being a PITA in many cases.

The old Particles and Metaballs method
I refer to this as the "poor mans’ fluids sim.
With the revamped Dynamics tools in c4d, just the right scene scale and enough particles and the proper effectors, one can achieve some pretty good motion results. That is until you need to mesh those results. Metaballs are the usual choice to create an envelope around the particles, but as we all know, rather than getting the finely detailed splash and spray of realflow, we get blobby spheres. With the right scene scale you can sometimes get very tight meshes around the particles, but in my experience, its a crapshoot and not a reliable way to work. It can work for quick shots. Perhaps a new metaball object with fluid meshing “algorhythms” (if thats a thing) would be all we needed to fill in the blanks?

Blender
This seems like a good way to go. Blender is very very inexpensive and includes (from what I’ve seen and heard) good fluid and liquid sim tools. I have heard from some c4d animatos who recommend Blender just for the fluid tools–and export the bin sequence (or whatever format it is) and import into c4d. I spent about 20 minutes in blender just trying to figure out how to rotate around the editor window and gave up. But I guess I could allocate some time and figure to out of I needed to. Would be interested in hearing how reliable Blender is when using (the exported sequences) in conjunction with C4D and NET.

Turbulence 4D
is great and relatively inexpensive–but it only handles gaseous fluids–not liquids.

DPIT EFFEX
Results look great from what I can see and runs right inside of C4D, which is a plus, however, it isn’t clear to me yet what one needs to do in order to render with NET. Is there a renderkit pakage of sorts that allows DPIT to be rendered on addiitonal render nodes? Would one need to purchase separate licenses for NET? I have heard others mention issues in this area but not sure myself. If needing to buy separate licenses for each node were the case, then an $890 license of DPIT could easily begin to approach (and surpass) the 4K USD cost of Realflow if one needs to buy a license for each node. But again–please clear up my confusion if I am incorrect here.

Thanks for reading and please add to the discussion if you have any recommendations or workflow suggestions.


#2

We’ve tried every simulation and all have their pros and cons, but the best choice is still Realflow, even as expensive as it is now. Realflow can handle pretty much any liquid situation (water, paste, chocolate, milk, mercury etc.) and is faster to get to the result you want compared to the others. Currently I consider Realflow to liquid simulations what Cinema is the 3D. We’ve had it for years and it used to be a LOT cheaper. You can import what’s basically a frame sequence obj mesh of the simulation, so there’s no need for a plugin for the farm.

Blender has an awesome liquid simulation function and is free, but the learning curve is daunting as their interface is…different. But it’s free! We’ve used blender a lot for FBX export to Unity and our AR software as it’s superior to Cinema as well.

DPIT will require a render farm to have the plugin and to my understanding, in the next release there might be a per client fee for using it, which will REALLY turn render farms off. With our ramped up projects we’ve had to consider many render farm options, including cloud based, and each plugin that does not have a cache solution or can be baked is pretty much dead if you have to go anywhere besides Render King. Also, again, it takes a lot more tweaking to get the result you’re looking for in DPIT than Real Flow.

Metaballs and particles…until metaballs gets a revamp that’s just an exercise in futility.

I’ve talked to Jascha at Jawset about creating a liquid simulator, since turbulence actually is one just tuned more for gaseous as I understand it. My vote would be for everyone to put pressure on Jawset to make one as I think Turbulence 4D is fast and easy to use and I think they could make a nice one.

I can’t think of the name of it now, but someone was developing another 3rd party simulator that looked amazing and had a Mac version, as good as RealFlow and cheaper, but I think Autodesk just aquired it a few months back, unfortunately.


#3

You’re probably referring to Naiad from Exotic Matter, which has, indeed, been acquired by Autodesk not long ago. I’ve seen some amazing Naiad liquid sims, most of them can be found on http://vimeo.com/channels/naiad/videos

No idea how gently it plays with c4d.


#4

Yeah, that’s it. My heart broke when they acquired it.


#5

it really depends on what type or liquid/fluid/gas/foam/honey etc you want to create and this then will determine the approach since each type of substance is better suited to differing methodologies…there is no one size fits all approach unless the tool itself changes it methodology dependant on substance i would say most don’t. So then its a case of choosing the tool thats best suited to the types of substances you intend to simulate. there are not a great deal of options for c4d anyway. Come at it in the same way you’re pick a renderer would be my advice…there isn’t a overall renderer and there isn’t and overall uber fluid sim


#6

I’d like to expand on the original question ("How does a small shop effectively manage to get fluids and liquids rendered for big projects with tight deadlines and limited budgets?) to include the question of how much time it takes to produce the simulation itself, before any rendering has taken place.

An important variable in any fluid dynamics workflow is “simulation iterations per hour”: how quickly can you make changes and adjustments based on client feedback or other factors? Do you have the storage capability to push around large amounts of data as quickly as possible? Will you need multiple machines and software licenses to produce variations of a simulation in parallel instead of sequentially? In larger productions, it’s not unusual for the simulations to run as long if not longer than the renders themselves, depending on complexity and fluid detail required in the final image. So having multiple machines running sims at the same time is common.

NextLimit offers node-only licenses of RealFlow, as well as short-term rental options so you can scale according to your needs as economically as possible, instead of having to commit to a large financial outlay upfront - assuming you have the extra machines at hand.


#7

Short answer: RealFlow. There is no problem to render with a local farm if you know how to do it.

BUT, the core question should be, if Maxon will renew its Thinking Particles engine, so you can actually work with some of the data at all.

Till then its the wrong question which fluid/liquid software to use in conjuction with C4D to expand your fluid/liquid portfolio. I’d rather question myself, if C4D serves the professional purpose.

As a sidenote, Turbulence FD looked very promising when development started but never continued to impress me as it stayed very limited in its usability even with smoke. Think about missing interaction possibilities, missing Age channel to work with, no Field-to Particle conversion etc…

Btw,

Me too, still waiting on your TFD Cookbook you been teasing about few months ago;)


#8

I used blender fluids with some success on a couple of jobs, in conjunction with an obj sequence reader.

It´s actually the only thing I can use in blender, but it did the job very easily and quickly. For splashing soda, ice cubes falling in a glass or chocolate bar in milk, that´s really neat.

You only need to care about the geometry as all the rest is dealt with in c4d (lights,shading,rendering…)

For smoke it´s more of a pain as I don’t know how to export the data over to C4D.

For open waters you might want to fake it with add-the-sea


#9

Thanks for sharing your thoughts.

@Mr. Tyler Durden:
You make a good point as to whether C4D is the right choice for doing this type of work. Obviously if one is going to focus on producing these types of dynamics sims for a living they are already working with software more suited to the vfx production pipeline. The issue however, (as it is for most c4d users) is that we have already invested in C4D for the long haul, and so we look for ways to do get the job done within those limitations. I do not plan on becoming a fluids TD by any means, but on the rare occasion where a client requires a splashing Nyquil logo, or a quick shot of churning stomach acids, I would like to have a plan.

As for Realflow, I have been considering it. It sounds like you have had success with rendering your files using NET. I have heard from others that this is a difficult process that sometimes will not work. Besides price, that would be the other factor which would make me think twice before purchasing. Thanks for your input.

@Eric M:
I still would like to explore Blender. Results I’ve seen look good–at least good enough for the kinds of things I would need it for (not planning on flooding NYC, for instance). Its just the navigation of the app itself that concerns me. But as with most things, that just requires some time and focus.

@lightdog:
Hi–thanks for your input.
All good points regarding the consideration for sim time. I have little experience with fluid sims, so hadn’t considered this factor. I guess I would cross that bridge when I came to it if I were to need more power to fuel the simulations. But the one thing I do know is that I would need to lean on a renderfarm for any large scale work I do, and am most interested in knowing which options will allow for NET rendering without the need for multiple licenses, or dealing with trial and error scenarios for having NET see the baked file sequences.

@Troyan:
Thanks–it sounds like its a resounding vote for Realflow. I vaguely remember having bought a license maybe 10 years ago or so, (I think) and foolishly did not stick with it. You have no trouble rendering your results on a farm? If not, that’s good.

Been hoping for some other tool to surface. Through Maxon or 3rd party. But its beginning to get to the point where sitting around and waiting is only lengthening the time in which I have noting to show for it. I guess its time to jump in.

THANKS all


#10

Found this old thread from Navstar in 2010 when the XSI plugin emPolygonizer2 was out.
Seems we’ve been talking about this stuff for quite a while now.

http://forums.cgsociety.org/showthread.php?t=914132


#11

guess its time for maxon to support these users and start to work to remove these limitations then…


#12

Net rendering is free for Effex. Download the demo, install, render. Everyone can use it on NET free of charge, on as many clients as you like.


#13

I chose Dpit Effex and I’m very happy with my decision. I would suggest trying out the v1.7 demo.


#14

Thanks Samir–good to know. I have been playing with the demo and it looks great. I havent tried installing it on the farm yet, but perhaps I’ll try that this coming week.


#15

Watch his tutorials on youtube, and join the Dpit forum to make learning it go a lot smoother.


#16

What about farms without Net Render like Render Rocket? Will you provide a free solution for that? And are you keeping the free render nodes model for the future?


#17

@Joel I have not tried 2012 on a farm but historically it worked fine.


#18

A major thing you have to consider in any of the plugins is would you be able to use that solution outside of Net Render. Render King is the only Cinema 4D exclusive render farm I’m aware of and the only farm that uses Net Render. All other farms basically use a command line or proprietary approach that allows them to farm render anything, and it’s no guarantee that any plugin will run at all outside of Net Render without some sort of baked or cached feature. The specs and demands are getting worse while deadlines and expectations of clients remain as if it was the same climate as 5 years ago. It’s getting harder to get projects done and profitable with a few local machines and RenderKing.


#19

I’ve witnessed fluid sim jobs from several vantage points. From doing them myself to being part of a pipeline where someone else did the sims, to watching a friend’s job go into meltdown because the fluid work wasn’t meeting the clients expectations. Here are some thoughts.

While rendering fluids is tricky, it’s a knowable time frame. But simulation time isn’t. I’ve run sims overnight expecting them to be done in the morning only to find the frame time has quadrupled and I’m nowhere near done. A fluids expert might see this coming, but not always. And sims require lots of refining. As far as I know fluid sims have to be sequential, so there’s no way to split the sim over several machines.

There’s no such thing as a low-res sim test. Well there is, but it’s not going to tell you enough about the sim to be very useful. Good sims need lots of detail and that takes time.

Simulating real fluids is easy. Simulating what your client wants isn’t. Anyone can grab a copy of realflow and simulate a glass of water filling up. But what happens when your client asks for the splash to happen in a certain way? Or for a droplet to behave just so? I watched a project go from piece of cake to utter nightmare in a few days because the client was asking for something physically impossible.

Fluids on their own are never enough. A decent bit of fluid work will need a lot of post. You’ll need to use the different output files your sim creates. Wet maps, foam maps, meshes, particles, a good fluid comp will take these and produce something magical. Realflow can produce these. But beware, their integration into C4D is not perfect. You will need time to test them. For instance it took me two days to figure out a workflow for using Realflow’s wet maps in C4D.

Before you use a fluid sim on a job, think about whether it really has to be a sim. I’ve jumped into Realflow a few times only to realise a few days layer that I could have done it better another way.

I hope that’s useful.

Will


#20

This is all pure gold–thank you Will.

I am usually able to work out a good solution that the client is satisfied with using only particles, mograph tools and sometimes just with deformers. Of course they’ve all been pretty simple cheats (a liquid pour with animated deformers, a splashing eye drop, running rivers and streams, things like this). I think it is always good practice to see if you can pull something off quickly and effectively with the tools we have before resorting to sims.

Your comments about getting a sim looking good right off the bat, only to have a client ask for specific subjective changes is a scenario I know well–as do many of us I’m sure. This also goes for any kind of GI or physical rendering approach, particle work, etc when under a tight deadline.

And this is one reason I try to steer clear of sims, or anything that is not tried and true where I have complete control and know I can get it to render quickly. I will definitely keep these suggestions in mind, as should we all.

Thanks.