Guide CS: Source — Fix "ERROR" Models on Modded Servers

[byte_corvus]

Sick of those giant red ERROR signs blocking your crosshair because a modded server has garbage asset management? This is a clean technical fix to overwrite custom or missing models with defaults before the engine tries to process them.

The Logic
We hook FrameStageNotify at stage 2 (FRAME_NET_UPDATE_POSTDATAUPDATE_START). At this point, RecvProxies have already written the server's custom m_nModelIndex, but the engine hasn't fully integrated it yet. By overwriting it with a default index, PostDataUpdate triggers SetModelIndex internally, handling bones and animations automatically without extra overhead.

// FrameStageNotify, stage 2
if (stage == 2) {
    int local_idx = engine->GetLocalPlayer();
    int highest = entitylist->GetHighestEntityIndex();
 
    for (int e = 1; e <= highest; e++) {
        if (e == local_idx) continue;
 
        IClientEntity* ent = entitylist->GetClientEntity(e);
        if (!ent) continue;
 
        C_BaseEntity* entity = ent->GetBaseEntity();
        if (!entity || entity->IsDormant()) continue;
 
        CBaseHandle owner = entity->GetOwnerEntity();
        if (owner.IsValid() && owner.GetEntryIndex() == local_idx) continue;
 
        ClientClass* cc = entity->GetClientClass();
        if (!cc) continue;
 
        const char* default_path = nullptr;
 
        switch (cc->m_ClassID) {
            case ClassId_CCSPlayer:
                default_path = (entity->GetTeamNumber() == TEAM_CT)
                    ? "models/player/ct_urban.mdl"
                    : "models/player/t_phoenix.mdl";
                break;
            case ClassId_CAK47:          default_path = "models/weapons/w_rif_ak47.mdl"; break;
            case ClassId_CWeaponM4A1:    default_path = "models/weapons/w_rif_m4a1.mdl"; break;
            case ClassId_CWeaponAug:     default_path = "models/weapons/w_rif_aug.mdl"; break;
            case ClassId_CWeaponSG552:   default_path = "models/weapons/w_rif_sg552.mdl"; break;
            case ClassId_CWeaponGalil:   default_path = "models/weapons/w_rif_galil.mdl"; break;
            case ClassId_CWeaponFamas:   default_path = "models/weapons/w_rif_famas.mdl"; break;
            case ClassId_CWeaponAWP:     default_path = "models/weapons/w_snip_awp.mdl"; break;
            case ClassId_CWeaponScout:   default_path = "models/weapons/w_snip_scout.mdl"; break;
            case ClassId_CWeaponSG550:   default_path = "models/weapons/w_snip_sg550.mdl"; break;
            case ClassId_CWeaponG3SG1:   default_path = "models/weapons/w_snip_g3sg1.mdl"; break;
            case ClassId_CWeaponMP5Navy: default_path = "models/weapons/w_smg_mp5.mdl"; break;
            case ClassId_CWeaponMAC10:   default_path = "models/weapons/w_smg_mac10.mdl"; break;
            case ClassId_CWeaponTMP:     default_path = "models/weapons/w_smg_tmp.mdl"; break;
            case ClassId_CWeaponUMP45:   default_path = "models/weapons/w_smg_ump45.mdl"; break;
            case ClassId_CWeaponP90:     default_path = "models/weapons/w_smg_p90.mdl"; break;
            case ClassId_CWeaponGlock:   default_path = "models/weapons/w_pist_glock18.mdl"; break;
            case ClassId_CWeaponUSP:     default_path = "models/weapons/w_pist_usp.mdl"; break;
            case ClassId_CWeaponP228:    default_path = "models/weapons/w_pist_p228.mdl"; break;
            case ClassId_CDEagle:        default_path = "models/weapons/w_pist_deagle.mdl"; break;
            case ClassId_CWeaponFiveSeven: default_path = "models/weapons/w_pist_fiveseven.mdl"; break;
            case ClassId_CWeaponElite:   default_path = "models/weapons/w_pist_elite.mdl"; break;
            case ClassId_CWeaponM3:      default_path = "models/weapons/w_shot_m3super90.mdl"; break;
            case ClassId_CWeaponXM1014:  default_path = "models/weapons/w_shot_xm1014.mdl"; break;
            case ClassId_CWeaponM249:    default_path = "models/weapons/w_mach_m249para.mdl"; break;
            case ClassId_CKnife:         default_path = "models/weapons/w_knife_t.mdl"; break;
            case ClassId_CC4:            default_path = "models/weapons/w_c4.mdl"; break;
            case ClassId_CHEGrenade:     default_path = "models/weapons/w_eq_fraggrenade.mdl"; break;
            case ClassId_CFlashbang:     default_path = "models/weapons/w_eq_flashbang.mdl"; break;
            case ClassId_CSmokeGrenade:  default_path = "models/weapons/w_eq_smokegrenade.mdl"; break;
            case ClassId_CBaseCSGrenadeProjectile: default_path = "models/weapons/w_eq_fraggrenade.mdl"; break;
            case ClassId_CHostage:       default_path = "models/hostage/hostage.mdl"; break;
            default: continue;
        }
 
        if (!default_path) continue;
 
        int default_idx = modelinfo->GetModelIndex(default_path);
        if (default_idx <= 0) continue;
 
        short* model_index = reinterpret_cast<short*>((uintptr_t)entity + 0xCC);
        if (*model_index == static_cast<short>(default_idx)) continue;
 
        *model_index = static_cast<short>(default_idx);
    }
}
 
// DrawModelExecute fallback: skip error models not covered above
void DrawModelExecute_hook(/* params */) {
    if (info.pModel) {
        studiohdr_t* hdr = modelinfo->GetStudiomodel(info.pModel);
        if (hdr && strstr(hdr->name, "error"))
            return;
    }
    original(/* params */);
}

Additional Safety
To catch anything missed in the loop, you can add a simple check in DrawModelExecute. If the studio header name contains "error", just skip the draw call. This ensures those floating red boxes never ruin your visibility.

void DrawModelExecute_hook(/* params */) {
    if (info.pModel) {
        studiohdr_t* hdr = modelinfo->GetStudiomodel(info.pModel);
        if (hdr && strstr(hdr->name, "error"))
            return;
    }
    original(/* params */);
}

Spoiler: Technical Notes

1. The offset used (0xCC) is standard for C_BaseEntity::m_nModelIndex in the CSS branch.
2. This method is significantly cleaner than attempting to block downloads as it allows the engine to use existing local assets.
3. Tested on standard v34 and Steam versions; works fine since model paths haven't changed in years.

This logic effectively forces a clean "Legit" look even on the most cluttered zombie or jailbreak servers. Anyone using a different hook for model normalization?