Riven Mod requirement out of left field...

[Iaini]

"Sustain a 3x melee combo multiple for 30 seconds alone"

is this even possible??? if so, where?? 

 

it's GOT to be a survival, frame of choice would likely be Inaros... but which mission!?!?

Edited November 21, 2016 by Iaini

[Aurea_Hiigara]

Body Count will help immensely. Go to an infested survival mission and just slash away.

[Vexagohn]

I went with Valkyr and my Telos Boltace with Blood Rush, Body Count and Berserker in it. Spammed Warcry in a survival infestation. But it took longer since you need to have 135 hits to get that 3x melee combo.

[Stormdragon]

I'd try using drifting contact + body count on any melee while doing a low level endless mission (I usually go to ceres survival Dark sector and get around 1K hits for the counter using only one of those mods) 

Edited November 21, 2016 by -----LegioN-----
Added node

[hr18]

Or alternatively Drifting Contact if you don't happen to have Body Count.

[Nurmetya]

If I recall I did one of those on one of the infested survivals on Eris, slapped the riven on a Zarr I was still leveling and grabbed galatine prime with body count and moved melee to the mouse wheel scroll and went nuts hit the 3x modifier in about a minute or so.

[Hakanasa]

Had this one once as well; nunchaku weapons come recommended since they strike multiple times per swing, builds that multiplier in pretty short order.

[S0V3REiGN]

Redeemer with bullet dance stance gets the 3x multiplier with in seconds. Body count and drifting contact will make its brezee.

[Arrectius]

Go with a tanky frame or loki for cheese on invisibility to a mid-high level survival, use a fast melee weapon with low damage or no mods at all (except fury) and you will reach that even without body count.

[Rolunde]

For mine I went to Ani in the Void which is basically a "T2" Survival.

To stack things as much as possible in my own favor I used-

Wukong with a traditional Rage/Defy build (actually picked him because of his Passive "(increasing the base combo counter from 3 seconds to 5 seconds)"

Orthos Prime with just Primed Reach, Primed Fury, Body Count and Drifting Contact (actually I probably left Maiming Strike on there as well but that's probably not too important).

I ended up having to do it twice as mine required the use of an active Companion. First run I had taken Helios with no weapon equipped and when I left found that apparently that wasn't good enough. So I swapped to my Smeeta Kavat and that time it worked. 

 So if you want to use Inaros I expect he should work totally fine as I never ended up having Defy ever need to trigger and Inaros is plenty tough.

The actual Melee Weapon choice probably doesn't really matter I just picked the OP because I figured since the whole point of this was to run up the melee combo multiplier to at least 3x I wanted to get it there as quick as possible and keep there as long as possible. So having a high melee range and attack speed all seemed like a good idea there.

The faster and farther you can hit the quicker it is to run up that combo counter and keep it there, bad spawns could mean having to go find enemies while that counter clock is ticking so again speed and reach helped with that.

In the end with a really high attack speed, melee range and a combo counter timer of 27 seconds even with the weapon still one-shot-ing everything I came across both times I had the combo at 3x in about 3 minutes or so.
(I didn't watch the clock too close to see how long it took but both times I had hit the 3x at least a minute or two before I could extract so I just kept running around melee killing all the things until the minimum 5 minutes were up and I could leave and see what my mod unveiled as!)  

One nice thing about having as high of a combo counter timer as possible is not only keeping it up if you have to run from room to room looking for enemies due to bad spawns but also if they're not being helpful about dropping atmosphere canisters.

My first run was great, lots of enemies in a small map constantly poring in  and dropping air, I never once needed to activate Life Support. My Second run ended up with a bigger map (larger more open rooms) and they didn't drop as much. Now it never got dangerously low but when it got down to about 60% I did start activating Life Support to get up up in the 90's again. After I did that a few times things seemed to pick up and there were still plenty of drops.

But my main point there is that if you have to activate Life Support that can take some time and since time is key here for the combo counter that's why I really wanted to build for the longest counter as possible and also have speed and reach to stretch that out even more.

OK so probably way more details than you needed but like I said in the end it was pretty smooth going for me that way and if I'd taken my Kavat with me the first time I'd have had it done in one and in less than 5 minutes (not counting having to run out the timer to extract).

Cheers!
~R~

P.S.
You probably already know this but just to make sure, you do have to have your Riven mod equipped on your Primary weapon and bring it along otherwise it won't get unveiled. 
Also you won't know for absolute certain it's been unlocked until you get back to your ship, just checking the End of Mission report won't indicate anything but when you get back to the ship what I will call the "Riven Unveiling Window" will pop up and show you what you got. 

[Iaini]

awesome, thanks I have Wokong so I can switch frames easily enough, unfortunately I don't have body count, but I'll make do. 

thanks again everyone. 

[Grenthy]

If you have a tanky frame ( I used Valkyr) you can go beat up ruk till it finishes. Even though he doesn't take damage, you can still rack up combo points.